EP3628416B1 - Process and system for continuously casting a metal product - Google Patents

Description

The invention relates to a method for continuously casting a metallic product according to the preamble of claim 1, and to a continuous casting installation according to the preamble of claim 10.

During the production of metallic products in a continuous casting plant, the liquid metal is continuously cast in a mold, where a first strand shell is formed. As a rule, the strand emerges downwards from the mold, the strand then being transported along a supporting strand guide. After exiting the supporting strand guide, the strand is then moved along a further strand guide with a straightening area, through which the strand is deflected in the horizontal direction. Following this, further processing stations for the strand or partial products formed therefrom can be provided along the strand guide, for example in the form of rolling mills through which the strand is passed.

In the continuous casting process, it is of great importance that the strand hardens or solidifies completely within the supporting strand guide in order to prevent the liquid metal core from breaking out and to enable the strand to be processed further. For this purpose, the cooling capacity in the area of the supporting strand guide and the casting speed are set in such a way that, with an optimal operating sequence, the sump tip of the strand is always in front of or upstream of the last pair of supporting rollers at the end of the supporting strand guide.

If during the continuous casting process, e.g. as a result of a too high casting speed, the sump tip of the strand is behind or downstream of the last pair of supporting rollers of the supporting strand guide and has thus "wandered out" of the supporting strand guide, the problem arises that the strand can bulge , because the hydrostatic pressure of the liquid melt now lacks a counterpressure due to a pair of supporting rollers. This can cause the Strand in a non-area of the strand guide, which does not contribute to the support of the strand and - seen in a conveying direction of the strand - is located downstream of the supporting strand guide, bulges develop due to an increase in the thickness of the strand.

According to the state of the art, it is over DE 1 558 345 A known to sense or scan bumps on unsupported areas of metal strands in the continuous casting process, namely by using mechanical sensors with rotatable and heat-resistant wheels that roll on the broad sides of the moving strand. Since these mechanical sensors can be moved to and fro, in a direction perpendicular to the direction of conveyance of the strand, bulges can be scanned which form when the strand bulges on at least one broad side thereof. In this case it can be provided to change the casting speed or to adjust the amount of water that is sprayed onto the moving strand in the area of the supporting strand guide.

The measuring principle according to DE 1 558 345 A , with which dents or an increase in thickness on the surface of a moving strand after exiting a supporting strand guide is determined in a mechanical way with a contact measuring roller, is subject to various disadvantages, e.g. wear of the wheels of the mechanical sensors due to the high temperatures of the strand . Furthermore, measurement errors can result if these wheels do not roll cleanly on the broad sides of the strand.

According to the prior art, it is also known to measure the thickness of the strand by using laser beams. However, such an optical method is subject to the disadvantage that water vapor, which can form in the measurement environment due to the cooling of the strand with water, then either blocks or at least deflects the laser beams, which leads to incorrect measurement results. Furthermore, the use of laser beams is also subject to the disadvantage of possible contamination of the aperture.

• eine Überhitzung, die im tatsächlichen Gießprozess höher ist als dem mathematisch-physikalischen Modell zugeführt wurde,
• zu große Maulweiten der Segmente der stützenden Strangführung, die im tatsächlichen Gießprozess höher sind als dem mathematisch-physikalischen Modell zugeführt wurde,
• reduzierte Sekundärkühlung, die im tatsächlichen Gießprozess geringer ist als dem mathematisch-physikalischen Modell zugeführt wurde,
• geänderte chemische Zusammensetzung des Werkstoffs, aus dem der Strang vergossen wird, wobei diese geänderte chemischen Zusammensetzung dem mathematisch-physikalischen Modell nicht zugeführt wurde, und/oder
• Modellfehler in dem mathematisch-physikalischen Modell.

In the continuous casting process, the position of the sump tip of the strand is usually monitored with mathematical-physical models. Still there is Reasons for the fact that the sump tip leaves the area of the supporting strand guide or runs out of it. These reasons can be:

• overheating that is higher in the actual casting process than was added to the mathematical-physical model,
• Too large mouth widths of the segments of the supporting strand guide, which are higher in the actual casting process than was added to the mathematical-physical model,
• Reduced secondary cooling, which is lower in the actual casting process than was added to the mathematical-physical model,
• changed chemical composition of the material from which the strand is cast, this changed chemical composition not being added to the mathematical-physical model, and / or
• Model error in the mathematical-physical model.

Out JP H02 55652 A It is known to change the casting speed during the production of a strand as a function of the measured strand shell thickness in order to thereby achieve a desired position for the sump tip of the strand. An ultrasonic measuring device is used to measure a strand shell thickness. A precise indication of the point at which such an ultrasonic measuring device is arranged relative to a supporting strand guide is given in FIG JP H02 55652 A not known. Furthermore it is off EP 2 422 900 A1 an arrangement for measuring physical parameters in continuous casting molds is known.

The invention is based on the object of optimizing the continuous casting of a metallic product with regard to quality improvement and at the same time increasing operational reliability, also with regard to preventing undesired bulging following the supporting strand guidance.

This object is achieved by a method according to claim 1 and by a continuous casting plant with the features of claim 10. Advantageous developments of the invention are defined in the dependent claims.

A method according to the present invention is for making a metallic product. In a continuous caster, a strand of the metallic product emerges continuously from a mold, in particular vertically downwards, and is then transported along a supporting strand guide in a conveying direction, the strand being deflected in a straightening area in the horizontal direction. In this method, in a step (i) a thickness of the strand is measured by a radar measuring device at a measuring position where the strand immediately leaves the supporting strand guide, and then in a step (ii) the measured strand thickness is compared with a first predetermined comparison value . Thereafter, in a step (iii), if the measured strand thickness is greater than the first predetermined comparison value, at least one casting parameter is changed in such a way that the sump tip of the strand migrates in the direction of the mold.

In the same way, the invention provides a continuous caster for producing a metallic product. Such a system comprises a mold and a supporting strand guide which adjoins the mold and along which a strand emerging from the mold, in particular vertically downwards, can be transported in a conveying direction. Following the supporting strand guide, another strand guide is provided with a straightening area through which the strand can be deflected in the horizontal direction. Furthermore, a radar measuring device with which a thickness of the strand can be measured at a measuring position located directly at the end of the supporting strand guide, and a control device with a computing unit connected to the radar measuring device for signaling purposes, with which the measured strand thickness with a first predetermined comparison value can be compared. The radar measuring device is arranged at a position where the strand emerges from the supporting strand guide. The control device is programmed in such a way that, if the measured strand thickness is greater than the first predetermined comparison value, then a control signal can be generated with which at least one casting parameter is changed in such a way that the sump tip of the strand moves in the direction of the mold.

The invention is based on the essential knowledge that the measurement of a thickness of the strand at a measuring position where the strand leaves the supporting strand guide directly is carried out by means of radar technology. For this purpose, a radar measuring device is arranged directly at the end of the supporting strand guide, namely where the strand emerges from the supporting strand guide. Compared to the prior art measurement methods mentioned at the beginning, radar measurement technology has the advantages that temperature radiation in the near IR range, which emanates from the hot strand, does not affect the radar measurement, and that in the measurement environment water vapor emanating from the Strand cooling by means of water is created without falsifying the measurement from the radar beams penetrating to the strand. In addition, a radar measurement is (more) insensitive to contamination compared to an optical measurement using a laser and a mechanical measurement using a touching measuring roller.

With regard to the positioning of the radar measuring device in the continuous caster, it is recommended that a relatively large distance from the hot strand is maintained. This is possible thanks to the non-contact radar measurement. Such a sufficiently large distance between the radar measuring device and the hot line ensures good protection of the radar electronics against the radiant heat emanating from the line.

The radar measuring device is arranged relative to the supporting strand guide and the strand emerging therefrom such that the radar beams or waves are directed essentially perpendicularly onto a surface of the strand, namely on its broad side (s). In this way, the radar beams are directed or transmitted perpendicularly by the radar measuring device onto the surface of at least one broad side of the strand.

In an advantageous further development of the invention, the radar beams are directed, starting from the radar measuring device, from both sides of the strand perpendicular to its broad sides. This ensures a uniform and complete measurement of the thickness of the strand immediately after it has emerged from the supporting strand guide, in connection with the detection of possible "bumps" on the surfaces of the broad sides. Such monitoring of the string from both sides can be achieved in that the radar measuring device has separate transmitting / receiving modules which are arranged on both sides of the broad sides of the string and emit their radar beams or waves essentially perpendicular to the broad sides of the string . In addition and / or as an alternative to this, the radar measuring device can also have separate parabolic elements which are arranged on both sides of the broad sides of the string and align the radar beams essentially perpendicularly to the broad sides of the string. By deflecting the radar beams in this way by means of the parabolic elements, the actual radar measuring device, with its sensitive transmitter / receiver unit, can be positioned at a sufficient distance from the hot strand and related components of the continuous caster.

A further improved protection of the radar measuring device against the high temperatures of the strand can be achieved by thermal insulation layers in which the radar measuring device is encapsulated. This is possible because radar rays penetrate such dielectric materials in the form of thermal insulation layers.

An important feature of the method according to the invention, and in the same way of a control device of the continuous casting plant according to the invention set up accordingly in terms of programming, is that, in the event that the strand thickness measured by the radar measuring device should be greater than the first predetermined comparison value, then at least one casting parameter in is changed in such a way that the sump tip of the strand migrates in the direction of the mold.

This means that by suitably changing at least one casting parameter, the sump tip - viewed in the direction of conveyance of the strand - is then displaced upstream and thus "migrates" back into the supporting strand guide. Said change of at least one casting parameter is expediently that the casting speed is reduced, but not set lower than a minimum casting speed at which the sump tip of the strand is below LiquidCoreReduction (LCR) segments of the supported strand guide. Additionally and / or alternatively, in the course of changing at least one casting parameter, the cooling capacity in the area of the supporting strand guide can also be increased.

For the purposes of the present invention, the first predetermined comparison value with which the strand thickness measured by the radar measuring device is compared in step (ii) is a distance between the last two support rollers at the end of the supporting strand guide, ie at its exit area, where the moving strand leaves the supporting strand guide. In this regard, it should be pointed out separately that at this distance between the two last support rollers, their deflection is also taken into account, which can occur when the strand is passed through between these opposite support rollers.

As explained above, depending on the strand thickness measured by the radar measuring device and in the event that this strand thickness is greater than the first predetermined comparison value (= distance between the last two support rollers at the end of the supporting strand guide), the casting speed can then be reduced become. In this regard, it should be emphasized that a reduction in the casting speed has a direct effect on the entire length of the strand, and thus also on the position of the sump tip of the strand, which is hereby shifted upstream, ie against the conveying direction of the strand in the direction of the mold.

With the present invention it is achieved that by means of a radar measurement the thickness of the strand after it has emerged from the supporting strand guide is measured exactly. In this way, possible bulges of the strand as it emerges from the supporting strand guide can be recognized precisely and reliably, in connection with the initiation of an immediate "countermeasure", preferably in the form of reducing the casting speed.

Fig. 1

eine schematisch vereinfachte Seitenansicht einer erfindungsgemäßen Stranggießanlage,

Fig. 2a

eine Seitenansicht einer stützenden Strangführung, die Teil der Stranggießanlage von Fig. 1 ist, in Verbindung mit einer RadarMesseinrichtung nach einer Ausführungsform der Erfindung,

Fig. 2b

eine Querschnittsansicht des Strangs an der Messposition der Stranggießanlage von Fig. 1, in Verbindung mit einer Radar-Messeinrichtung nach einer weiteren Ausführungsform der Erfindung,

Fig. 3, 4

jeweils schematisch vereinfachte Seitenansichten von verschiedene Betriebstellungen einer stützenden Strangführung, die Teil der Stranggießanlage von Fig. 1 ist, und

Fig. 5

ein Flussdiagramm zur Erläuterung des Ablaufs eines erfindungsgemäßen Verfahrens, das z.B. mit einer Stranggießanlage von Fig. 1 durchgeführt werden kann.

Embodiments of the invention are described in detail below with reference to a schematically simplified drawing. Show it:

Fig. 1

a schematically simplified side view of a continuous caster according to the invention,

Fig. 2a

a side view of a supporting strand guide that is part of the continuous caster of Fig. 1 is, in connection with a radar measuring device according to an embodiment of the invention,

Figure 2b

a cross-sectional view of the strand at the measuring position of the continuous caster of FIG Fig. 1 , in connection with a radar measuring device according to a further embodiment of the invention,

Fig. 3, 4

each schematically simplified side views of different operating positions of a supporting strand guide, which are part of the continuous caster of Fig. 1 is and

Fig. 5

a flow chart to explain the sequence of a method according to the invention, which is carried out, for example, with a continuous caster from FIG Fig. 1 can be carried out.

With reference to the Figs. 1 to 5 preferred embodiments of a continuous caster 10 according to the invention and a corresponding method for producing a metallic product are explained. The same features in the drawing are each given the same reference symbols Mistake. At this point, it is pointed out separately that the drawing is only shown in a simplified manner and, in particular, without a scale.

The continuous casting installation 10 according to the invention comprises a mold 12, which is followed by a supporting strand guide 13 with a total of four segments 13.1-13.4. As evidenced by the representations in Fig. 3 or. Fig. 4 liquid metal is poured into the mold 12 in the region of a melt inlet 6, with a strand S with an initially still liquid core 7 then entering downward from the mold 12 into the supporting strand guide 13. In the segments 13.1-13.4 of the supporting strand guide 13 there are each oppositely arranged pairs of supporting rollers 14, 14 ', between which the strand is moved in the conveying direction F. These pairs of supporting rollers 14, 14 'are each acted upon by displacement or position-controlled hydraulic cylinders, not shown in detail, so that they can overcome the hydrostatic pressures of the melt 8 and thereby cause a local thickness reduction in the strand. This applies in particular to the first two segments 13.1, 13.2 of the supporting strand guide 13, where the strand S with its liquid core 7 can be reduced in thickness by compressing the segments, which is also referred to as LiquidCoreReduction (= LCR).

At one end 15 of the supporting strand guide 13, ie where the strand S emerges from the supporting strand guide 13 in the conveying direction F, there is a last pair of supporting rollers 14L, 14L '(cf. Fig. 3 , Fig. 4 ) intended. It is of great importance for the continuous casting process that the strand is already completely solidified before it passes through this last pair of supporting rollers 14L, 14L at the end 15 of the supporting strand guide 13. This is ensured by the fact that a sump tip SP of the strand S is still located within the supporting strand guide 13, as shown in FIG Fig. 4 is illustrated. In this way, a bulging of the strand S following the supporting strand guide 13, also referred to as "whale formation", can be effectively prevented.

The continuous caster 10 comprises, as evidenced by the side view of FIG Fig. 1 , a further strand guide 19 with a straightening area I, in which the strand S is deflected by bending rollers 22 in the horizontal direction. Following the straightening area I, a pair of scissors 23 is arranged in the strand guide 19, followed by at least one rolling mill 24 and a furnace 26 arranged in front of it.

Furthermore, the continuous casting plant 10 comprises a radar measuring device 16 with which a thickness of the strand S is measured at a measuring position 18, namely immediately where the strand leaves the supporting strand guide 13 after passing through the last pair of supporting rollers 14L, 14L ' exit. This measurement position 18 is indicated by an arrow in Fig. 1 illustrated.

In one embodiment of the radar measuring device 16 - as evidenced by the side view according to FIG Fig. 2a - Radar beams directed essentially perpendicularly to the two broad sides of the strand S. For this purpose, the radar measuring device 16 has separate transmitting / receiving modules 16.1, 16.2, which are each arranged on both sides of the broad sides of the strand S, and with which radar beams are then each directed perpendicularly onto the surface of a broad side of the strand. In this regard, it is pointed out that a distance between these transmit / receive modules 16.1, 16.2 from the supporting strand guide 13 and the hot strand S guided therein is sufficiently large so that these modules are not damaged by the thermal radiation emanating from the strand S.

In a further embodiment of the radar measuring device 16 according to FIG Figure 2b Separate parabolic elements 17.1, 17.2 are provided, which are arranged on both sides of the broad sides B1, B2 of the strand S in order to thereby direct the radar beams essentially perpendicularly onto the broad sides B1, B2. This makes it possible to arrange the actual radar measuring device 16 in the radiation shadow, whereby a further improved protection against the thermal radiation of the string S is guaranteed.

The continuous casting plant 10 comprises a control device 20 with a computing unit 21, which is connected for signaling purposes to the radar measuring device 16, the bending rollers 22 in the region of the strand guide 19 and the at least one rolling mill 24, in Fig. 1 each symbolized by dotted lines. This ensures that, on the one hand, the strand thickness measured by the radar measuring device 16 is transmitted to the arithmetic unit 21 and, on the other hand, the arithmetic unit 21 also provides information regarding both a distance between the bending rollers 22 and the distance from (not shown) Work rolls of the rolling mill 24 receives. Furthermore, the arrows in the Fig. 1 from the control device 20 to both the mold 20 and the shears 23, symbolizes that suitable control signals can be generated by the control device 20 in order to change both a casting speed in the mold 12 and the shears 23 - if necessary - to be operated as explained separately below.

The invention now works as follows:

_{In the ongoing continuous casting process, a minimum casting speed V min is} determined on the basis of the current process values (chemical analysis of the material, strand thickness, set cooling capacity for the segments 13.1-13.4 of the supporting strand guide 13), at which the sump tip SP below the two LCR segments 13.1, 13.2 (see illustration in Fig. 4 ). The radar measuring device 16 continuously measures a thickness of the strand S, as explained above at the measuring position 18, ie immediately where the strand S emerges from the end 15 of the supporting strand guide 13. This corresponds to a step (i) of a method according to the present invention, the measured strand thickness being transmitted to the computing unit 21 of the control device 20. Following this, namely in a step (ii) of the method according to the invention, the measured strand thickness is compared with a first compared with a predetermined comparison value, which corresponds to a distance between the two last support rollers 14L, 14L '.

If then in a step (iii) of the method according to the invention it should be determined by the computing unit 21 that the strand thickness of the strand S measured with the radar measuring device 16 is greater than the first predetermined comparison value (= distance between the two last support rollers 14L, 14L 'from one another ), there is a risk that the sump tip SP of the strand S is either already outside (or below, viewed in the conveying direction F of the strand S) of the supporting strand guide 13, as in FIG Fig. 3 is illustrated, or at least there is a tendency for the sump tip SP to shift there. In this case, the control device 20 immediately generates a control signal with which, for example, the casting speed is set to a reduced value V _red . It should be noted here that the reduced casting speed V _red always remains greater than the minimum casting speed V _{min explained above.} Compliance with this condition ensures that the sump tip SP of the strand S does not migrate too far "upwards", that is to say it reaches the area of the two LCR segments 13.1, 13.2.

After the casting speed has been set to the reduced value V _red , a query is carried out in the arithmetic unit 21 for the further course of the continuous casting process as to whether the strand thickness measured by the radar measuring device 16 in step (i) is less than a predetermined second comparison value , which corresponds to a distance from oppositely arranged bending rollers 22. If a "No" is determined in this query, meaning that the strand thickening of the strand S can no longer be transported through the bending rollers 22, the control device 20 emits a control signal for an immediate interruption of casting in order to avoid further damage to the strand guide 19 the continuous caster 12 to avoid.

Otherwise, a further query takes place in the computing unit 21 as to whether the strand thickness measured by the radar measuring device 16 in step (i) is less than a predetermined third comparison value, which corresponds to a distance between oppositely arranged work rolls in the rolling mill 24. If a "No" is determined in this query, this is synonymous with the fact that the existing strand thickening in the rolling mill 24 cannot be brought to a desired final dimension. Therefore, the control device 20 then generates a control signal for the scissors 23, by means of which the thickened section of the strand S is separated from the strand guide 19 and shredded accordingly.

The above-mentioned step sequences for the method according to the invention are also shown in the flowchart from FIG Fig. 5 shown accordingly.

List of reference symbols

6th

Melt inlet

7th

liquid core

8th

melt

10

Continuous caster

11

metallic product

12th

Mold

13th

supporting strand guide

13.1-13.4

Segments (of the supporting strand guide 14)

14, 14 '

Role pairs (of a respective segment 14.1-14.4)

15th

End (of the supporting strand guide 13)

16

Radar measuring device

16.1, 16.2

Transmit / receive modules (of the radar measuring device 16)

17.1, 17.2

Parabolic elements (of the radar measuring device 16)

18th

Measuring position

19th

Strand guide (not supported)

20th

Control device

21

Arithmetic unit

22nd

Bending rolls

23

scissors

24

Rolling mill

26th

oven

B1, B2

Broad sides (of strand S)

F.

Conveying direction

I.

Straightening area

S.

strand

SP

Swamp tip

Vred

reduced casting speed

Vmin

minimum casting speed

Claims (14)

1. Method for continuous casting of a metallic product (11), in which in a continuous casting plant (10) a strip (S) of the metallic product (11) exits continuously from a mould (12), in particular vertically downwardly, and is subsequently transported along a supporting strip guide (13) in a conveying direction (F), wherein the strip (S) is deflected in a straightening region (I) into the horizontal direction,
   characterised by

   (i) measuring a thickness of the strip (S) by a radar measuring device (16) at a measuring position (18) where the strip (S) directly leaves the supporting strip guide (13),

   ii) comparing the measured strip thickness with a first predetermined comparison value and

   iii) if the measured strip thickness is larger than the first predetermined comparison value: changing at least one casting parameter in such a way that the end (SP) of liquid phase of the strip (S) migrates in the direction of the mould (12).
2. Method according to claim 1, characterised in that the casting speed is reduced in step iii).
3. Method according to claim 2, characterised in that on the basis of instantaneous process values for the ongoing casting process a minimum casting speed (V_min) is determined in which the end (SP) of liquid phase of the strip (S) lies below LCR segments (13.1, 13.2) of the supporting strip guide (13), wherein the reduced casting speed (V_red) is selected to be higher than the minimum casting speed (V_min).
4. Method according to any one of the preceding claims, characterised in that the first predetermined comparison value corresponds with a spacing of the two last backing rollers (14L, 14L') at the end (15) of the supporting strip guide (13).
5. Method according to any one of the preceding claims, characterised in that the cooling output in the region of the supporting strip guide (13) is increased in step iii).
6. Method according to any one of the preceding claims, characterised in that the strip thickness measured in step (i) is compared with a second predetermined comparison value, wherein if the measured strip thickness is larger than the second predetermined comparison value the casting process is then interrupted.
7. Method according to claim 6, characterised in that the second predetermined comparison value corresponds with a spacing from bending rollers (22) of the further strip guide (19), the bending rollers being arranged opposite one another particularly in the straightening region (I).
8. Method according to any one of the preceding claims, characterised in that the strip thickness measured in step (i) is compared with a third predetermined comparison value, wherein if the measured strip thickness is larger than the third predetermined comparison value then a region of the strip (S) having a strip thickness greater than the third predetermined comparison value is separated out from the strip guide by means of shears (23).
9. Method according to claim 8, characterised in that the third predetermined comparison value corresponds with a spacing of work rolls in a rolling mill (24) in which the hardened strip (S) is further processed.
10. Continuous casting plant (10) for producing a metallic product (11), comprising a mould (12), and
    a supporting strip guide (13) which is connected with the mould (12) and along which a strip (S) exiting, in particular vertically downwardly, from the mould (12) is transportable in a conveying direction (F),
    a further strip guide (19), which is connected with the supporting strip guide (13), with a straightening region (I) by which the strip (S) can be diverted into the horizontal direction, characterised by
    a radar measuring device (16) which is arranged at a position (18) where the strip (S) exits the supporting strip guide (13), so that a thickness of the strip (S) at a measuring position (18) lying directly at the end (15) of the supporting strip guide (13) can be measured by the radar measuring device (16),
    a control device (20), which is in signal connection with the radar measuring device (16), with a computing unit (21) by which the measured strip thickness can be compared with a first predetermined comparison value, wherein the control device (20) is arranged to be programmed in such a way that if the measured strip thickness is larger than the first predetermined comparison value then a control signal can be generated by which at least one casting parameter is varied in such a way that the end (SP) of liquid phase of the strip (S) migrates in the direction of the mould (12).
11. Continuous casting plant (10) according to claim 10, characterised in that the radar measuring device (16) is so arranged that radar beams are directed perpendicularly from both sides onto the wide sides (B1, B2) of the strip (S).
12. Continuous casting plant (10) according to claim 11, characterised in that the radar measuring device (16) comprises separate transmitting/receiving modules (16.1, 16.2) which are arranged on either side of the wide sides (B1, B2) of the strip (S).
13. Continuous casting plant (10) according to claim 12, characterised in that the radar measuring device (16) comprises separate parabola elements (17.1, 17.2) which are arranged on either side of the wide sides (B1, B2) of the strip (S).
14. Continuous casting plant (10) according to any one of claim 10 to 13, characterised in that shears (23) in signal connection with the control device (20) are arranged in the further strip guide (19), wherein the shears (23) are activatable by the control device (20) if the strip thickness measured by the radar measuring device (16) is larger than a spacing of work rolls in a rolling mill (24) arranged downstream of the shears (23) as seen in the conveying direction (F) of the strip (S).

Images