EP3177412B1 - Adjustment of a targeted temperature profile on the strip head and strip foot before transversally cutting a metal strip - Google Patents

Description

Field of engineering

The present invention relates to the field of metallurgical plants, specifically a rolling mill with a cooling zone for cooling and a pair of scissors for cutting metal strips, preferably steel.

• Führen des Metallbandes in einer Transportrichtung durch eine Kühlzone;
• Abkühlen des Metallbandes in der Kühlzone; anschließend
• Querteilen des Metallbandes an einer Schere, sodass das Metallband in einen vorlaufenden Metallbandabschnitt mit einem Bandfuß des vorlaufenden Metallbandabschnitts und einen nachlaufenden Metallbandabschnitt mit einem Bandkopf des nachlaufenden Metallbandabschnitts quergeteilt wird und der Bandkopf des nachlaufenden Metallbandabschnitts in Transportrichtung dem Bandfuß des vorlaufenden Metallbandabschnitts unmittelbar nachfolgt,

On the one hand, the invention relates to a method for cross-cutting a metal strip, preferably a steel strip, the method comprising the following steps:

• Guiding the metal strip in a transport direction through a cooling zone;
• Cooling the metal strip in the cooling zone; subsequently
• Cutting the metal strip on a pair of scissors such that the metal strip is transversely divided into a leading metal strip section with a strip foot of the leading metal strip section and a trailing metal strip section with a strip head of the trailing metal strip section and the strip head of the trailing metal strip section immediately follows in the transport direction the strip foot of the leading strip metal section;

On the other hand, the invention relates to a device for cutting a metal strip for carrying out the method according to the invention, with a roller table for guiding the metal strip, 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 leading metal band section (28) with a band foot of the leading Metal strip portion (32) and a trailing metal band portion (29) with a tape head of the trailing metal band portion (31) is divided transversely and the tape head of the trailing metal band portion (31) in the transport direction of the band foot of the leading metal band portion (32) immediately follows.

State of the art

Hereinafter, a pair of scissors, e.g. can be designed as pendulum scissors, referred to before the finishing train as a separator. A pair of scissors arranged after the finishing train and in front of the reel, e.g. can be designed as a drum shears, 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 rolled the metal strip finished in batch mode. However, this has the consequence - to ensure a sufficient gap between the tape foot and 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 Plant parts such as the induction furnace, finishing train and the cooling zone are traversed faster. When passing through the finishing train it also comes due to the higher speed to temperature increases which has a negative effect on the mechanical belt properties and on the surface quality. In order that the mechanical properties of the metal strip remain homogeneous over the length, the process parameters of the plant parts must be adapted accordingly in order to avoid unfavorable temperature increases. The cooling pattern of the cooling zone must also be adjusted accordingly. 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 the WO / 59650 is a system with a Strangußanlage, a roughing mill, a separator, a furnace of a coiler, a Descaler, a finishing train, a cooler, a pair of scissors and again a coiler 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 transversely divided band foot and also already physically present tape head are then overheated in an induction furnace and wound by means of the coiler. Subsequently, the metal strip is unwound from the reel and finish-rolled in a finishing train. Due to the overheated band head and band foot of the metal band, this system is particularly suitable for rolling thin metal sheets of> lmm. The overheating of the tape head and the strip foot lead to comparable qualities as is the case with cold-rolled metal strips. After a cooling device, a pair of scissors is arranged, which can cross the thin hot-rolled metal strip, if necessary again on tape length.
In the EP0730916 A1 a hot rolling mill is shown, comprising the following plant parts, a continuous casting plant, an oven, a rolling train, a pair of shears and a coiler. 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 of the metal strip thickness can be detected and the scissors is controlled by this tracking device. Upon detection of a change in thickness - the metal strip - the scissors is activated for cutting. In the subsequent coiler, the metal strip is finally wound up.

The preamble of claims 1 and 14 is based on the EP0730916 A1 ,

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 metal strip, so that the metal strip in the region of the tape head of the trailing metal band section and Bandfußes the leading metal band section has a higher temperature 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 cooled and then carried out a cross-section of the metal strip on the scissors, so that the transversely divided metal strip has a tape head of the trailing metal band section and a band foot of the leading metal band section. The tape head is the beginning of a metal strip in the transport direction. The band foot of the leading metal band portion is the end of the leading metal band portion after the cross cutting. 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. Band head of the trailing metal band section and band foot of the leading metal band section are defined before entering the cooling device and not only after the 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 strip sections are created. The metal strip sections are part of the metal strip until they are cross-cut. After completion of cross-cutting and finished winding of the leading metal band portion, the previously following metal band portion for the next transverse parts to the leading metal band portion. In the region of the band head of the trailing metal band section and band foot of the leading metal band section, a temperature profile is set by the cooling zone, which has a higher temperature than in the upstream and downstream areas.
Due to the higher temperature in the region of the band head of the trailing metal band section and the band foot of the leading metal band section, the yield stress is preferably reduced by up to 50%. For very high-strength steel grades, the reduction of yield stress can even be> 50%. The expended for the cutting of the band cutting forces are reduced accordingly. The cross-cutting of the metal strip can be done easily with a common scissors used. Thus, it can be waived, 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 region of the band head of the trailing metal band section and band foot of the leading metal band section is constantly tracked (i.e., 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 metal band section are already defined before the metal strip enters the cooling zone. By tracking the tape head of the trailing metal band section and band foot of 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. However, it is also possible to use other temperature profiles, for example a jump profile or a sinusoidal temperature profile.

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 the forces to be expended when cutting cross.

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 are those of high and very high strength 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.

This method makes it possible that even high-strength 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, with the same system configuration, with a standard used scissors, for example, a metal strip of dual-phase steel DP1000 with a thickness of 8mm can be easily divided transversely. 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 by the supplied in the cooling zone amount of cooling medium. The temperature profile is set in the cooling zone in the region of the band head of the trailing metal band section and the band foot of the leading metal band section by the cooling medium in this area is not applied or only to a reduced extent.
During the passage of the tape head of the trailing metal band section and the band foot of the leading metal band 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. With a discrete set amount either 100% of the cooling medium is applied or 0%. This has the advantage that the cooling zone can be easily performed without requiring expensive actuators - eg for adjusting 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 method can also be used in existing systems without major alterations. Particularly preferred, this method can be used for ESP (Endless Strip Production) systems. This has the clear advantages that with the same system configuration, the endless operation can be extended to high-strength grades and larger thicknesses, without having to accept adverse effects on the strip properties.

A further advantageous embodiment of the method is that the metal strip is wound on a reel after the cross-cutting. 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 of a metal strip section with increased temperature ≥ a circumference of a coil, so that the coil is wrapped warm by the band foot of the leading metal band portion. The increased temperature of the band foot of the leading metal band section additionally has the positive effect of resulting in a more uniform cooling of the metal band. Since the outermost layer cools faster than the underlying layer, the cooling process is more uniform over the entire length of the wound metal strip, resulting in 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-cutting of the metal strip is a particularly advantageous embodiment that a knife gap of the scissors is adjusted depending on the thickness of the metal strip. As a result, the process of cross-cutting, even during operation, be further optimized and the cutting forces are further reduced depending on the thickness of the metal strip. In a first approximation, there is a linear dependence of the ideal knife gap on the thickness of the metal strip.

• eine Nachverfolgungseinrichtung zur Nachverfolgung vom Bandkopf des nachlaufenden Metallbandabschnitts und Bandfuß des vorlaufenden Metallbandabschnitts zumindest von Beginn der Kühlvorrichtung bis zur Schere,
• eine Steuereinrichtung zur Steuerung der Kühlvorrichtung und der Schere in Abhängigkeit der Position von Bandkopf des nachlaufenden Metallbandabschnitts und Bandfuß des vorlaufenden Metallbandabschnitts.

The object according to the invention is also achieved by the device mentioned at the outset, which comprises the following:

• a tracking device for tracing the tape head of the trailing metal belt section and belt foot of the leading metal belt section at least from the beginning of the cooling device to the shears,
• a control device for controlling the cooling device and the scissors as a function of 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 shows EP0730916 a tracking device which detects a change in the strip thickness. By this tracking device then a pair of scissors is controlled. A tracking device from the beginning of the cooling device until reaching the scissors is not shown in this document. Similarly, a control of the cooling device based on the position of the tape head and tape foot is not shown. 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, wherein the at least three cooling sections can be controlled or regulated separately from one another. By at least 3 separate cooling sections ensures that the temperature profile can be reliably transferred to the metal strip. When the region of the band head of the trailing metal band section and band foot of the leading metal band section - which is to have a greater temperature - reaches the cooling section, the first cooling section in the transport direction is switched off, while the remaining cooling sections remain switched on. When the area of the strip head of the trailing metal strip section and strip foot of the leading metal strip section - which is to have a higher temperature - approaches a second cooling section, it is also switched off and as soon as the area of the strip head of the trailing metal strip section and strip foot of the leading metal strip section - the larger one Temperature should - has left the first cooling section, this is turned on again. When approaching the region of the tape head of the trailing metal band section and band foot of the leading metal band section - which should 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 band foot of the leading metal band section - have a higher temperature should - have left the second cooling section again, the second cooling section is turned on again. This is done analogously for all other cooling sections which the cooling device has. When exactly the respective cooling section to be switched on or off depends on which temperature profile is to be transferred to the metal strip and how many cooling sections has the cooling device. 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.

In order to be able to ensure the tracking of the position of the band head of the trailing metal band section and band foot of the leading metal band section particularly precisely, it is particularly advantageous if the tracking device has a computing device and at least one position or speed sensor which controls the cooling device in such a way before the cross-section of the metal band in that the desired temperature profile is established in the region of the band head of the trailing metal band section and band foot of the leading metal band section. The position or velocity sensor may be a contacting (e.g., a roller press or a reel speed) or non-contact (optically, e.g., via a laser) design.

With regard to the embodiment of the cooling device, it is expedient to carry out the cooling device as a water cooling section.

In a particularly advantageous manner, the cooling device is designed such that the flow rate of water nozzles of the cooling device in the transport direction can be controlled or regulated individually or in sections by an adjusting device which is connected to the control device. The water nozzles are mounted on spray bars. If one considers the individual spray bars along the transport direction, which extend across the entire width of the metal strip transversely to the transport direction, then each spray bar represents the smallest section. Tubes or nozzles can be located on these spray bars, through which the water emerges. 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 band head of the trailing metal band section and band foot of the leading metal band section is carried out in an advantageous embodiment 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-cutting of the metal strip is a particularly advantageous embodiment, that the scissors has a device for adjusting the knife gap, wherein the means for adjusting the knife gap, the current thickness of the metal strip 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 adjustment of the knife gap is made according to the thickness of the metal strip. It gets bigger, the larger the metal band is, which is split.

• Fig. 1 eine schematische Darstellung einer Gieß-Walz-Verbundanlage nach dem Stand der Technik.
• Fig. 2 eine schematische Darstellung einer Gieß-Walz-Verbundanlage zum erfindungsgemäßen Querteilen von Metallbändern.
• Fig. 3a und Fig. 3b zeigt das warme Einpacken eines Coils.
• Fig. 4 zeigt ein erfindungsgemäßes Temperaturprofil eines Metallbandes.
• Fig. 5a und Fig. 5b zeigen Ausführungsvarianten eines Positionssensors und eines Geschwindigkeitssensors.
• Fig. 6 zeigt ein Diagramm der Fließspannung über die Temperatur aus M. Spittel und T.Spittel Landolt-Börnstein Group VIII: Advanced Materials and Technologies, Volume 2, Springer Verlag, 2007, S. 11 .
• Fig. 7a und Fig. 7b zeigen das erfindungsgemäße Temperaturprofil eines Metallbandes kurz vor und kurz nach dem Querteilen

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 a schematic representation of a casting-roller complex system according to the prior art.
• Fig. 2 a schematic representation of a cast-rolling composite plant for the inventive cross-cutting of metal strips.
• Fig. 3a and Fig. 3b shows the warm wrapping of a coil.
• Fig. 4 shows an inventive temperature profile of a metal strip.
• Fig. 5a and Fig. 5b show embodiments of a position sensor and a speed sensor.
• Fig. 6 shows a graph of yield stress versus temperature 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 show the temperature profile of a metal strip according to the invention shortly before and shortly after the cross-cutting

Fig.1 shows a cast-rolling composite plant 1. In normal operation, a continuous casting plant 2 generates a continuously cast continuous material 3 with slab cross-section, which is transported by means of a roller table 4 to a roughing mill 5. After the rough rolling in the roughing 5, the metal strip 6 reaches the separator 7. According to the prior art was here the cross-cutting of the metal strip 6 using the separator 7 - which is a pendulum scissors in this case. Thereafter, 4 driven gaps between the metal belts 6a-6d by driven rollers of the roller table. The figure also shows the tape heads 31a-31d produced after the transverse cutting as well as the tape feet 32a-32d. After the passage of the induction furnace 8, the finishing train 9 and the cooling zone 10, the winding of the metal strip takes place on the reel 13th

In Fig. 2 An embodiment according to the invention of the device for cutting metal strips is shown. The first steps up to Vorwalzstraße 5 are analogous to the prior art in Fig. 1 , Thereafter, no transverse parts, but the metal strip 6 passes undivided through the induction furnace 8, the finishing train 9 and then passes to the cooling zone 10. Before the metal strip 6 enters the cooling zone 10 is detected by means of a first temperature sensor 15, the actual temperature of the metal strip 6 and the controller 14 sent. In the cooling zone 10, the desired temperature profile is applied to the metal strip 6 by the Wasserprühbalkenabschnitte 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 metal band portion 31 and band foot of the leading metal band portion 32 of the metal strip 6 (see Fig. 4 below) are determined by the control device 14, by means of the position sensor 16 and the computing device 22, and their position is determined 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 (optically eg via a laser) design. The position sensor 16 and the computing device 22 form the tracking device 23. The spray bars 21 can be adjusted according to the predetermined temperature profile over the entire passage of the tape head of the trailing metal band section 31 and band foot of the leading metal band section 32. After passing through the cooling device 19, the metal strip 6 has a higher temperature in the area of the strip head of the trailing metal strip section 31 and strip foot of the leading metal strip section 32 than in the upstream and downstream areas. After complete passage of the tape head of the trailing metal band 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 trailing metal band portion 31 and band foot of the leading metal band portion 32 has arrived at the scissors 12 receives this, by the controller 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 is shown 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 T ₀ , a metal band section 33 of length L with temperature T ₁ and the band foot 32a. The length L of the metal band section is the length of the circumference of the coil 30. The temperature of the metal band section 33 in this case has a higher temperature T ₁ as the temperature T _{0 of} the preceding part of the metal strip. In the diagram, the temperature T over the metal strip length x - this is about the extended length - shown.
In Fig. 3b it can then be seen that the warm metal band section 33 encloses the coil 30.

In Fig. 4 a typical inventive temperature profile over the temperature profile length xp of a metal strip 6 is shown. In the area of the strip foot of the leading metal strip 32 - over the strip foot length xf - the temperature T _{1 is} higher than after, where a temperature T _{0 is} set, until finally the area of the tape head of the trailing metal band portion 31 follows in which also - over the tape head length xk - Again, a temperature T _{1 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 leading metal strip 28 also has a temperature profile with the temperature T ₁ . The metal strip 6 is divided into a leading metal strip section 28 and a trailing metal strip section 29 after the transverse cutting on the scissors. 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 strip section 28 and trailing metal section 29.

In Fig. 5a an embodiment of a position sensor 16 is shown in more detail, the roller 41 is pressed onto the metal strip 6. By the movement of the metal strip, the pressed-on roller 41 rotates and this is detected by an optical sensor 42 and the signal generated thereby is further processed in the control device 14. By this signal and various other information such as the desired length of the metal strip, the position of the later tape head and tape foot at least in the range from the beginning of the cooling zone 10 to the scissors 12 can be calculated by the controller 14. The spray bar sections 20 and, if appropriate, the individual spray bars 21 in the cooling zone 10 are controlled such that a desired temperature profile is established on the metal strip 6.

In Fig. 5b an embodiment of a speed sensor 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 other information that is relevant for the production - such as the desired length of the metal strip - again the position of the tape head 31 and band foot 32 in the cooling zone 10 can be determined ,

In Fig. 6 is the behavior of the yield stress σ _F over 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 can be greatly reduced.

In Fig. 7a the metal band 6, immediately before the cross-cutting, is shown. The band foot of the leading metal band portion 32 and the band head of the trailing metal band portion 31 are still identical before the cross-cutting and exist only as an imaginary plane. The leading metal strip section already knows a tape head 31a on - which has originated from the previous cross parts. In Fig. 7b is the cross-cutting already done. This results in - in the 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 cutting a band head 31 a and the band foot of leading metal band section 32. 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 section 32 have the temperature profiles shown.

LIST OF REFERENCE NUMBERS

1

Gießwalzverbundanlage

2

Continuous casting plant

3

Raw material

4

roller table

5

roughing

6,6a-6d

metal band

7

separator

8th

induction furnace

9

finishing line

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

Sprühbalkenabschnitte

21

spray

22

computing device

23

tracking device

28

leading metal band section

29

Trailing metal band section

30

coil

31

Band head of the trailing metal section

31a-31d

band head

32

Bandfoot of the leading metal section

32a-32d

strip foot

33

Metal strip section

34

transport direction

41

role

42

Optical sensor

43

Angle encoder

L

Length of the metal band section

T

temperature

xp

Temperature profile length

xf

Bandfußlänge

xk

Band head length

x

Metal band length

σ _f

yield stress

Claims (20)

1. Method for cross-cutting a metal strip (6), preferably a steel strip, wherein the method comprises the following steps:

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

   - cool down the metal strip (6) in the cooling zone (10); then

   - cross-cut the metal strip (6) on shears (12), so that the metal strip (6) is cross-cut into a preceding section of metal strip (28) having a strip tail (32) of the preceding section of metal strip and a following section of metal strip (29) with a strip head (31) of the following section of metal strip and, in the direction of transport (34), the strip head (31) of the following section of metal strip follows on immediately after the strip tail (32) of the preceding section of metal strip,

   characterised in that the metal strip (6) is cooled down in the cooling zone (10) to a prescribed temperature profile in the lengthwise direction of the metal strip (6) so that, in the region of the strip head (31) of the following section of metal strip and the strip tail (32) of the preceding section of metal strip, the metal strip (6) has a higher temperature than in the preceding and following regions.
2. Method according to claim 1, characterised in that the region of the strip head (31) of the following section of metal strip and the strip tail (32) of the preceding section of metal strip is constantly tracked, at least from the start of the cooling zone (10) up to the shears (12).
3. Method according to one of the preceding claims, characterised in that the temperature profile concerned is a ramp profile.
4. Method according to one of the preceding claims, characterised in that the temperature in the region of the strip head (31) of the following section of metal strip and of the strip tail (32) of the preceding section of metal strip lies at least 100 °C above that of the rest of the metal strip (6).
5. Method according to claim 4, characterised in that the region of the strip head (31) of the following section of metal strip and the strip tail (32) of the preceding section of metal strip is uncooled.
6. Method according to one of the preceding claims, characterised in that the metal strip (6) consists of high and ultra-high strength materials, preferably these are pipe or hot strip multi-phase steels or fully martensitic steels.
7. Method according to one of the preceding claims, characterised in that the metal strip (6) has a thickness > 4mm.
8. Method according to one of the preceding claims, characterised in that the temperature profile is set by a quantity of coolant fed onto the metal strip (6) in the cooling zone (10).
9. Method according to claim 8, characterised in that the quantity of coolant fed is adjusted discretely.
10. Method according to one of the preceding claims, characterised in that before it is cooled down in the cooling zone (10) the metal strip (6) is rolled on a rolling line of a combined casting/rolling facility (1).
11. Method according to one of the preceding claims, characterised in that after cross-cutting the metal strip (6) is wound up on a coiler (13).
12. Method according to claim 11, characterised in that the length of a partial piece (33) of the metal strip which has a raised temperature is ≥ the circumference of a coil (30), so that the coil (30) is hot-packed by the strip tail (32) of the following section of metal strip.
13. Method according to one of the preceding claims, characterised in that a blade gap of the shears (12) is set as a function of the thickness of the metal strip (6).
14. Facility for cross-cutting a metal strip (6), for carrying out the method in accordance with one of the preceding claims, with a roller track (4) for feeding the metal strip (6), with at least one cooling facility, wherein the cooling facility (19) is arranged before shears (12) for cross-cutting the metal strip, so that the metal strip (6) is cross-cut into a preceding section (28) of metal strip with a strip tail (32) of the preceding section of metal strip and a following section (29) of metal strip with a strip head (31) of the following section of metal strip, and the strip head (31) of the following section of metal strip follows in the direction of transport immediately behind the strip tail (32) of the preceding section of metal strip, characterised by

    - a tracking facility (23) for tracking the position of the strip head (31) of the following section of metal strip and the strip tail (32) of the preceding section of metal strip, at least from the start of the cooling facility (19) up to the shears (12), and

    - a control facility (14) for controlling the cooling facility and the shears (12) as a function of the position of the strip head (31) of the following section of metal strip and the strip tail (32) of the preceding section of metal strip
15. Facility according to claim 14, characterised in that the cooling facility has at least three cooling sections which are separate from each other, wherein the at least three cooling sections can be controlled or regulated separately from each other.
16. Facility according to claim 14, characterised in that the tracking facility (23) has a computing facility (22) and a position sensor (16) or speed sensor (18) for the metal strip (6).
17. Facility according to one of claims 14 to 16, characterised in that the cooling facility (19) is a water cooling line.
18. Facility according to one of claims 14 to 17, characterised in that the amount of flow through the water jets of the cooling facility (19) can be controlled or regulated in the direction of transport (34) individually or in sections, by a setting facility which is linked to the control facility (14) .
19. Facility according to claim 14, characterised in that the tracking facility (23) is a temperature measurement facility.
20. Facility according to one of claims 14 to 19, characterised in that the shears (12) have a facility for adjusting the blade gap, wherein the current thickness of the metal strip (6) can be fed to the facility for the purpose of adjusting the blade gap.

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