EP3025799A1 - Rolling mill, casting roller system and method for generating a metal strip - Google Patents

Abstract

The invention relates to a rolling mill, a casting-rolling plant and a method for producing a metal strip. In particular metal strip with thicknesses> 6 mm particularly effective, d. H. can be heated and rolled using as little electrical energy, the invention proposes that a Längsfeldinduktor 170 is disposed between at least one roughing stand 420 and a first stand F1 a finishing train and that an upper Längsfeldinduktor-displacement device 140 is provided for moving the upper induction coil 110 of the Längsfeldinduktors perpendicular to the top of the metal strip 200 and / or a lower Längsfeldinduktor-displacement device is provided for moving the lower induction coil 120 of Längsfeldinduktors perpendicular to the underside of the metal strip. With the help of the displacement devices, the distance d of the upper induction coil 110 from the upper side of the metal strip and / or the distance d of the lower induction coil 120 from the underside of the metal strip in a working position to d <60 mm is set.

Description

The invention relates to a rolling mill comprising at least a first and a second rolling stand, at least one arranged between the first and the second roll stand inductor for heating a metal belt moved by the inductor, wherein the inductor, an upper induction coil, which is arranged above the metal strip to be heated and a lower induction coil disposed below the metal strip to be heated and opposite to the upper induction coil. In addition, the rolling mill comprises a power supply device for supplying the upper and the lower induction coil with electrical energy. Moreover, the invention relates to a casting-rolling plant with a casting machine for producing the metal strip and a rolling mill downstream of the casting machine in the material flow direction according to the invention. Moreover, the invention finally also relates to a method for producing a metal strip.

Inductors for heating metal strip are known in the art in principle, such. B. from the GB 770,548 , of the JP 022 07 481 , of the JP 06122928 , of the JP 2000-252050 , of the JP 2004 306069-71 , of the WO 2010 036987 A2 and the WO 2014 021596 , The cited documents describe further remote prior art.

Furthermore, please refer to the JP 4172122 which discloses vertically engageable inductor halves which are moved vertically when a ski is detected at the head of a metal strip with the aid of a camera to avoid collision of the metal strip with the inductor. The upper and lower induction coils are moved vertically according to a measured tape position. However, the said Japanese application speaks only of an inductor without distinguishing between transverse field or longitudinal field inductors.

The US 5,495,094 discloses inductor loops with a 180 ° phase shift, which thus represent a longitudinal field inductor. The inductor loops are each independently adjustable perpendicular to a stationary workpiece to be heated.

The use of longitudinal and transverse field inducers in a rolling train is disclosed in US 5,356,367 EP 2 416 900 B1 , The WO 2012 045585 A2 discloses a laterally open transverse field inductor for entering the line or from the line of a metal strip in a rolling train.

The EP 0 721 813 A1 discloses a C-shaped inductor between two adjacent rolling stands in a finishing train and moreover all the features of the preamble of claim 1.

In said state of the art, a distinction is made between longitudinal field and transverse field inductors. Transverse field inductors are used primarily for heating thin strips with thicknesses <12 mm, while longitudinal field inductors are used for heating thicker strips with thicknesses> 6 mm, for example. Depending on the design and boundary conditions as well as a selected frequency range, there is a transition range for the practicable use of the two induction heating types; please refer EP 2 416 900 B1 ,

FIG. 9 shows the structure and operation of a known Querfeldinduktors 180. It includes an upper transverse field induction coil 182, which is associated with the top of the metal strip 200. In addition, the transverse field inductor comprises a lower transverse field induction coil 184, which is associated with the underside of the metal strip 200. As in FIG. 9 2, the opening cross-sections of the upper and lower transverse field inductor coils are opposite to each other and parallel to the metal strip 200. The magnetic field lines generated in operation of the inductor are shown in FIG FIG. 9 also shown symbolically. The upper and lower Querfeldinduktorspule 182, 184 are each independently movable perpendicular to the plane of the metal strip 200, that is adjustable. As the course of the field lines shows, the magnetic field or the magnetic flux acts primarily perpendicular to the plane of the metal strip. The split arrangement of the coils advantageously makes it possible for the two induction coils, ie for both inductor halves, to be arranged independently of one another perpendicularly to the plane of the metal strip and for the inductor to be formed laterally open. In the event of a fault, the distance between the coils and the metal strip can therefore be increased slightly and / or the inductor can be moved out of the line of the metal strip.

FIG. 8 shows an example of a known Längsfeldinduktor, which is typically formed as a closed frame. The metal strip to be heated therefore passes through a closed rectangular gap when passing through the known longitudinal field inductor. As in FIG. 8 can be seen, generates the Längsfeldinduktor substantially a magnetic field in the transport direction of the metal strip to be heated.

The said definitions and the shape of transverse and longitudinal field inductors are also from the WO 2014 021596 known.

Starting from the in the EP 0 721 813 A1 disclosed prior art, the present invention seeks to develop a known rolling mill, a known casting-rolling plant and a known method for producing a metal strip to the effect that particularly thicker metal strip with thicknesses, for example> 6 mm heated and rolled particularly effective ie using as little electrical energy as possible.

• dass es sich bei dem ersten Walzgerüst um mindestens ein Vorgerüst und bei dem zweiten Walzgerüst um ein erstes Walzgerüst aus einer Mehrzahl bzw. Reihe von Walzgerüsten einer Fertigwalzstraße handelt,
• dass die Energieversorgungseinrichtung ausgebildet ist, die obere und die untere Induktionsspule des Induktors mit gegenphasigen elektrischen Strömen und damit dem Induktor als Längsfeldinduktor zu betreiben,
• dass eine obere Längsfeldinduktor-Verfahreinrichtung vorgesehen ist zum Verfahren der oberen Induktionsspule senkrecht zur Oberseite des Metallbandes und/oder eine untere Längsfeldinduktor-Verfahreinrichtung vorgesehen ist zum Verfahren der unteren Induktionsspule senkrecht zur Unterseite des Metallbandes, und
• dass der Abstand der oberen Induktionsspule von der Oberseite des Metallbandes oder der Abstand der unteren Induktionsspule von der Unterseite des Metallbandes in einer Arbeitsposition weniger als 60 mm, vorzugsweise weniger als 20 mm beträgt.

This object is achieved by the rolling mill according to claim 1. This is characterized

• in that the first rolling stand is at least one roughing stand and the second rolling stand is a first rolling stand from a plurality or series of rolling stands of a finishing train,
• in that the energy supply device is designed to operate the upper and the lower induction coil of the inductor with opposite-phase electrical currents and thus with the inductor as a longitudinal field inductor,
• in that an upper longitudinal field inductor-moving device is provided for moving the upper induction coil perpendicular to the upper side of the metal strip and / or a lower Längsfeldinduktor-displacement device is provided for moving the lower induction coil perpendicular to the underside of the metal strip, and
• the distance of the upper induction coil from the upper side of the metal strip or the distance of the lower induction coil from the underside of the metal strip in a working position is less than 60 mm, preferably less than 20 mm.

The main advantage of the invention of a new induction heating for a rolling mill, in particular a hot strip mill, is to combine the advantages of the inductor types described above, namely the possibility of adjusting the upper and lower inductor coils and the efficient heating of thicker strips or slabs.

Of particular importance is the adjustability or the method of the upper and / or lower Längsfeldinduktorspulen perpendicular to the metal strip when the metal strip thickness in the field of longitudinal field induction heaters of z. B. 6-20 mm - d. H. to z. B. ΔH = 14 mm - or in another application between z. B. 32-70 mm - d. H. to z. B. ΔH = 38 mm - varies. In general, the adjustability of the split longitudinal field inductors makes sense in thickness variations of ΔH ≥6 mm or more preferably ΔH ≥ 15 mm.

When using a Vorgerüstes within a z. B. conventional rolling mill loses the Vorband between the roughing mill and the first rolling stand of the finishing line particularly quickly to temperature. In particular, the "waiting" end of the tape cools down, because it must stay longer before the finishing train or just colder. This requires higher rolling forces in the finishing train when rolling the strip end. The provision according to the invention of an induction heater in the form of an inductor advantageously makes it possible to increase the temperature level at the band end as well as over the entire band length as far as necessary. The control of the inductor with antiphase currents, so that the inductor can be operated as Längsfeldinduktor between the roughing stand and the first stand of the finishing train, offers the advantage of more efficient heating, especially in thicker bands. Finally, the further claimed mobility of the upper and lower induction coil perpendicular to the plane of the metal strip allows the advantage that the distance between the two coils to the metal strip can be adjusted individually optimally with regard to the respective metal strip thickness, so that as possible effective heat transfer into the metal strip is possible. In practice, in a working position, ie when the metal strip runs during operation of the rolling mill without interference by the inductor, a distance of less than 60 mm, preferably less than 20 mm in each case an induction coil to the metal strip is sought. Advantageously, a minimum distance of 15 mm has been shown.

Due to the claimed combination of the measures mentioned, in particular thicker metal strips with thicknesses of, for example, greater than 6 mm are optimally heated before entering a finishing train.

The terms "inductor coil" and "induction coil" are used synonymously in the description.

According to a first embodiment, the power supply device has upper capacitors, which are connected to the upper induction coil to an upper part of the resonant circuit, and the power supply device lower capacitors, which are connected to the lower induction coil to a lower resonant circuit. The upper Längsfeldinduktor-displacement device is then designed for moving the upper part of the resonant circuit perpendicular to the top of the metal strip and / or the lower Längsfeldinduktor-displacement device is then designed for moving the lower resonant circuit perpendicular to the underside of the metal strip.

The above-described operation of the upper and lower induction coil of the inductor with antiphase electric currents enables the inductor, ie the longitudinal field inductor, to be C-shaped. This advantageously also allows the transverse process of the Längsfeldinduktors in and out of the line of the metal strip. The possibility from the line of Pulling out metal strip is particularly advantageous in case of a fault in the rolling mill or in the presence of a wave in the metal strip or in the presence of a ski at the head of the metal strip.

The upper and the lower induction coil can each be formed from a single turn or from a plurality of parallel and preferably cross-connected partial turns. The provision of a single turn is often chosen at high frequencies. To effect the most uniform possible current distribution in the parallel connection of turns, is a fall, d. H. to provide a cross-connection of the windings. This technique, which is known from the field of electric motor technology, ensures that an external conductor is arranged in the forward conductor and the return conductor inside. By this crosswise interconnection, the current load of the parallel conductor is made uniform. Since the conductors must cross at the winding heads, they should be carried out particularly Streufeldarm. The cross-connection also equal Teilinduktivitäten be achieved.

The power supply device is advantageously designed to operate the induction coils and the partial resonant circuits - depending on the thickness of the metal strip - with current or voltage frequencies between 2 kHz and 30 kHz. The frequency increases with decreasing strip thickness.

Depending on the frequency, the number of partial turns per induction coil is between 3 and 15. The larger the number of partial turns, the finer the distribution of the current. But also the complexity of the inductor increases with a larger number of partial turns. The inductor windings are typically covered with laminations of laminated, laminated electrical sheets to reduce stray field. This measure is useful and necessary because the upper and lower induction coils are installed in close proximity to other rolling mill components. Because the others Rolling mill components are made almost exclusively from ferritic materials, no stray field must emerge from the induction coils of the longitudinal field or transverse field inductor and also heat up the other rolling mill components.

In addition to the claimed Längsfeldinduktor between the at least one roughing stand and the first rolling mill of the finishing train and at least one Querfeldinduktor be provided in the rolling mill, which can then be operated in addition to the at least one Längsfeldinduktor. The transverse field inductors are not only intended to heat the center of the tape, but at the same time, the strip edges are increasingly heated to efficiently produce a uniform strip temperature over the finished strip width.

An upper Querfeldinduktorspule or an upper Querfeldinduktor-part resonant circuit and a lower Querfeldinduktorspule and a lower Querfeldinduktor-part of the Querfeldinduktors are then also by means of associated Querfeldinduktor-displacement each perpendicular to the plane spanned by the metal strip plane and / or transversely to the longitudinal direction of the metal strip ,

The upper and lower Querfeldinduktor-displacement device and / or the upper and / or lower Längsfeldinduktor-displacement device are typically controlled by a control device.

A temperature measuring device may be provided for detecting the distribution of the temperature of the metal strip over its width, and the control device may then be designed to control the upper and / or lower Längsfeldinduktor-displacement device, the upper and / or lower Querfeldinduktor-displacement device and / or an inductor carriage such that the longitudinal field inductor or the transverse field inductor can be positioned in response to the measured temperature distribution such that the difference between the measured temperature distribution and a predetermined desired temperature distribution over the width of the metal strip behind the finishing train is minimal. Several longitudinal field or transverse field inductors may preferably be distributed over the length of the system.

Alternatively or additionally, a sensor device may be provided for detecting an irregularity in the metal strip, such as a ski at the head of the metal strip, a wave or a bow in the metal strip or any other disturbance of the rolling process. Also in this case, the control device is designed to control the upper and / or lower Längsfeldinduktor-displacement device and / or the upper and / or lower Querfeldinduktor-displacement device and / or the induction trolley such that the distance of the induction coil from the top or bottom of the Metal strip is suitably changed in the range of irregularity and / or the inductors are moved out of the line of the metal strip out.

Furthermore, at least one touch sensor may be provided for detecting a contact of the Längsfeldinduktors and / or Querfeldinduktors by the metal strip. In this case, the control device is designed to control the traversing devices such that the longitudinal field inductor and / or the transverse field inductor is opened in the thickness direction and / or is moved laterally out of the line of the metal strip.

Through the use of Liquid Core Reduction, ie a change in the slab thickness within the casting plant, the thicknesses with which the metal strip from the casting plant enters an oven or the at least one roughing stand of the rolling mill change. Even within the rolling mill behind a roughing stand or between the individual rolling stands of a finishing train, the thicknesses of the metal strip change in each case. Due to their adjustability transverse to the metal strip level, the claimed longitudinal field and Querfeldinduktoren in each case optimally adjusted to the individual thickness of the metal strip. Because the inductors, in particular the Längsfeldinduktoren, each C-shaped or laterally open, they are also good for larger tolerances with respect to the lateral extent of the metal strip well used.

The above object is achieved with respect to the casting-rolling plant by the subject-matter of claim 16. The advantages of this solution correspond to the advantages mentioned above with respect to the claimed rolling mill.

An oven can be connected between the caster and the rolling train, and advantageously, for further heating, a further longitudinal field inductor and / or the transverse field inductor can be connected between the furnace and the roughing stand. Particularly advantageous is the arrangement of the further Längsfeldinduktors between the furnace and the at least one roughing stand, and the arrangement of the Längsfeldinduktors between the roughing stand and the first stand of the finishing train and the arrangement of a transverse field inductor between individual stands of the finishing train.

With regard to the method, the above-mentioned object is achieved by the claims 19 to 26. The advantages of this procedural solution correspond to the advantages mentioned above with respect to the rolling mill and the casting-rolling plant.

Further advantageous embodiments of the rolling mill, the casting-rolling plant and the method according to the invention are the subject of the dependent claims.

• Der Einsatz von geteilten, anstellbaren Induktionsspulen des Längsfeldinduktors eignet sich insbesondere für Dicken des Metallbandes > 6 mm, weil in diesem Dickenbereich der erfindungsgemäße nicht geschlossene Längsfeldinduktor einen besseren Wirkungsgrad bietet als der Querfeldinduktor und/oder der mit Rahmenstruktur ausgebildete geschlossene Längsfeldinduktor. Der erfindungsgemäße geteilte, anstellbare Längsfeldinduktor wird vorzugsweise bei einem Bandtemperaturbereich von > 750°C verwendet. Er eignet sich insbesondere zum Endloswalzen (Definition siehe weiter unten) oder auch zum konventionellen Walzen von Flachprodukten in einer Warmbandstraße. Der Abstand d der Induktorfläche von dem Metallband, d. h. der Abstand zwischen der dem Metallband zugewandten Seite bzw. Fläche einer Induktionsspule zu dem Metallband beträgt während des aktiven Betriebs des Längsfeldinduktors, wie gesagt, vorzugsweise weniger als 20 mm. Beim Anfahren der Anlage oder bei einer Störungsbeseitigung kann ein Sicherheitsabstand der Induktionsspulen zum Metallband auch mehr als 100 mm, in Ausnahmefällen auch mehr als 500 mm betragen.

Further general statements on the subject matter of the invention:

• The use of split, engageable induction coils of the longitudinal field inductor is particularly suitable for thicknesses of the metal strip> 6 mm, because in this thickness range, the non-closed Längsfeldinduktor invention provides better efficiency than the Querfeldinduktor and / or formed with a frame structure closed Längsfeldinduktor. The split, adjustable Längsfeldinduktor invention is preferably used at a belt temperature range of> 750 ° C. It is particularly suitable for continuous rolling (definition see below) or for conventional rolling of flat products in a hot strip mill. The distance d of the inductor surface from the metal strip, ie the distance between the side facing the metal strip or surface of an induction coil to the metal strip during the active operation of the Längsfeldinduktors, as stated, preferably less than 20 mm. When starting up the system or when troubleshooting, a safety distance of the induction coil to the metal strip may be more than 100 mm, in exceptional cases, more than 500 mm.

The split, engageable longitudinal and transverse field inductors are preferably used in an endless casting-rolling process. In this procedure, the casting plant and the rolling mill are connected via the cast strand. Both systems are then coupled and work with the same mass flow. This process has to be started sometime and it is then that an induction heater, which consists of split inductors (top, bottom), which are adjustable and laterally open, particularly advantageous. This construction is also advantageous during the start-up and Ausfädelprozess or in a fault situation.

• Bei diesem Einfädelvorgang des Bandkopfes ist/sind die teilbaren Längsfeldinduktoren weiter geöffnet oder/und alternativ in Warteposition neben dem Band, weil mit einem Band-Ski oder Bandwellen bzw. -bögen gerechnet werden muss.
• Nach Passieren des jeweiligen Induktors oder nach Aufbau eines Bandzuges zwischen den zwei Gerüsten oder zwischen einem Gerüst und Treiber werden die geöffneten Induktoren auf den engen Betriebsabstand, d. h. eine enge Arbeitsposition angestellt oder erst in die Walzlinie gebracht und dann angestellt.
• Erst in Betriebsposition oder nahe der Betriebsposition wird der jeweilige Induktor aktiviert und das Band durch den Induktor geheizt.
• Bei Verstellung (z. B. Verminderung) der Dicke werden die Induktorpositionen entsprechend nachgefahren (z. B. enger gestellt).

Start-up of the continuous casting roll process using split, adjustable longitudinal field inductors:

• In this Einfädelvorgang the tape head / the divisible Längsfeldinduktoren is further opened or / and alternatively in waiting position next to the band, because with a band-ski or tape shafts or sheets must be expected.
• After passing through the respective inductor or after building a strip tension between the two stands or between a scaffold and driver, the open inductors to the close operating distance, ie hired a close working position or brought into the rolling line and then hired.
• Only in the operating position or near the operating position of the respective inductor is activated and the belt is heated by the inductor.
• Upon adjustment (eg reduction) of the thickness, the inductor positions are retraced accordingly (for example, narrower).

• Kurz bevor das Bandende das Gerüst vor der jeweiligen Induktorstrecke verlässt und der Bandzug abgebaut wird, wird der teilbare Längsfeldinduktor wieder geöffnet oder/und der Induktor herausgefahren, um auch dort eine Beschädigung oder Berührung der Induktoren zu vermeiden. Diese Fahrweise muss nicht zwangsläufig stattfinden, die Anlage kann aber sicherheitshalber so betrieben werden.

Doweling the end of the slab after the end of casting or discontinuing the continuous casting rolling process:

• Shortly before the end of the tape leaves the framework in front of the respective inductor section and the strip tension is reduced, the divisible longitudinal field inductor is opened again and / or the inductor is moved out to avoid damage or contact with the inductors there as well. This procedure does not necessarily take place, but the system can be operated as a precautionary measure.

• Kommt es zu einem Walzunfall oder andere Massenflussstörungen im Filetteil des Bandes so besteht die Gefahr, dass sich ein Bandbogen im Bereich des Induktors bildet und eine Berührung des Bandes am Induktor stattfindet. Auch in diesem Fall wird der geteilte Längsfeldinduktor geöffnet.
• Zur Störungsbeseitigung wird der Längsfeldinduktor ggf. auch aus der Walzlinie heraufgefahren.
• Eine eventuelle Berührung des Bandes an dem Induktor wird durch optische oder mechanische Sensoren detektiert. Vorteilhafterweise werden Bewegungssensoren z. B. Beschleunigungsgeber am Längsfeldinduktor oder an einer Längsfeldinduktorgruppe angebracht (oben oder/und ggf. unten). Bei einem Berührungssignal oder Berührungsgefahr wird die Längsfeldinduktionsheizung entsprechend oben, unten oder beidseitig aufgefahren.

Fault protection during the rolling process:

• If there is a Walzunfall or other mass flow disturbances in the fillet part of the band so there is a risk that a ribbon arc forms in the region of the inductor and a contact of the band takes place at the inductor. Also in this case, the split longitudinal field inductor is opened.
• If necessary, the longitudinal field inductor is also raised from the rolling line to eliminate the fault.
• Any contact of the tape to the inductor is detected by optical or mechanical sensors. Advantageously, motion sensors z. B. acceleration sensor at Längsfeldinduktor or attached to a Längsfeldinduktorgruppe (above or / and possibly below). In the case of a touch signal or danger of contact, the longitudinal field induction heater is raised correspondingly at the top, bottom or on both sides.

The above procedure or use of engageable inductors preferably takes place in continuous strip casting processes, in particular between two finishing stands, which have a stand spacing of 5 m to <40 m and which are operated in endless mode.

To control the approach and Ausfädelstrategie in endless strip casting process, a process model is used, which / controls the setting of the rolling stands and activation of the inductors or regulates.

In particular, the belt areas of different belt temperature are tracked through the rolling train and taken into account the effect of temperature differences on the framework load and scaffolding. That is, the cold one The tape head is set to a higher tape thickness and limits the decreases and so z. B. the framework load is kept within acceptable limits.

Figur 1

eine Walzanlage mit eingebauten erfindungsgemäßen Induktoren;

Figur 2

die Wirkungsweise des erfindungsgemäßen Längsfeldinduktors zwischen dem Vorgerüst und dem ersten Gerüst der Fertigwalzstraße;

Figur 3

einen Längsfeldinduktor gemäß der vorliegenden Erfindung;

Figur 4

Verfahreinrichtungen für einen Längsfeld- oder Querfeldinduktor senkrecht zur Ebene des Metallbandes sowie einen Induktionswagen zum Verfahren des Längs- oder Querfeldinduktors quer zum Metallband;

Figur 5

die Verwendung einer Temperaturmesseinrichtung und Sensoreinrichtungen zum Detektieren einer Unregelmäßigkeit in dem Metallband zum geeigneten Verfahren der Induktoren;

Figur 6

eine Gieß-Walz-Anlage mit einem Beispiel für den Einsatz der erfindungsgemäßen Längsfeld- und Querfeldinduktoren;

Figur 7

den Wirkungsgrad der erfindungsgemäßen geteilten anstellbaren Längsfeldinduktoren in Abhängigkeit der Banddicke und im Vergleich zu Längsfeldinduktoren mit geschlossener Rahmenstruktur und zu Querfeldinduktoren;

Figur 8

einen Längsfeldinduktor mit geschlossener Rahmenstruktur gemäß dem Stand der Technik; und

Figur 9

einen Querfeldinduktor gemäß dem Stand der Technik

zeigt.The invention is accompanied by nine figures, wherein

FIG. 1

a rolling mill with built-in inductors according to the invention;

FIG. 2

the mode of action of the longitudinal field inductor according to the invention between the roughing stand and the first stand of the finishing train;

FIG. 3

a longitudinal field inductor according to the present invention;

FIG. 4

Traversing devices for a longitudinal field or Querfeldinduktor perpendicular to the plane of the metal strip and an induction trolley for moving the longitudinal or Querfeldinduktors transverse to the metal strip;

FIG. 5

the use of a temperature measuring device and sensor devices for detecting an irregularity in the metal strip for the appropriate method of the inductors;

FIG. 6

a casting-rolling plant with an example of the use of Längsfeld- and Querfeldinduktoren invention;

FIG. 7

the efficiency of the split engageable Längsfeldinduktoren invention as a function of the strip thickness and compared to Längsfeldinduktoren closed frame structure and to Querfeldinduktoren;

FIG. 8

a Längsfeldinduktor with closed frame structure according to the prior art; and

FIG. 9

a Querfeldinduktor according to the prior art

shows.

The invention will now be described in detail in the form of embodiments with reference to said figures. In all figures, the same technical elements are designated by the same reference numerals.

FIG. 1 FIG. 1 shows an exemplary embodiment of the rolling mill 400 according to the invention. It comprises a roughing stand 420 and a finishing mill 440 which is connected downstream of the roughing stand in the material flow direction and has the finishing rolling stands F1-F _N. In the material flow direction R, the rolling mill 400 includes a cooling device 450 and a coiler 460 behind the finishing train 440.

Between the roughing stand 420 and the first rolling stand F1 of the finishing train 440, a longitudinal field inductor 170 designed according to the invention is arranged. In addition, transverse field inductors 180 or further longitudinal field inductors 170 may be arranged in front of the finishing train and / or between individual stands of the finishing train 440.

FIG. 2 illustrates the operation of the longitudinal field inductor 170: Without the presence of the Längsfeldinduktors 170, the temperature of the metal strip in z. B. the conventional rolling mill according to the solid line in FIG. 2 before the entry into the first stand F1 of the finishing train 440 from the tape head to the end of the tape fall off sharply. This would result in the disadvantages mentioned in the general part of the description. Advantageously, the Längsfeldinduktor invention causes between the roughing stand 420 and the First stand F1 of the finishing train 440 that the temperature of the metal strip 200 from the tape head to the end of the tape can be kept at a high level constant, as in FIG. 2 indicated by the horizontal dashed line.

From the roughing stand, the tape head can run out with a ski. This is eliminated or reduced according to the prior art before the induction heating with a roller leveler. If this does not succeed and a ski is still detected, the opening band is moved back and deported. This is disadvantageous.

A split longitudinal field inductor whose opening width can be increased (lifting the upper inductor and / or lowering the lower inductor) can ensure safe transport through the induction heating section primarily at the head. Depending on whether a ski or ribbon bow is detected or even a rolling failure occurs or also generally without tape form detection, the inductor distance is increased. After passing through the tape head (eg ski-holding), the inductor can then be closed again and the pre-strip heated. It can be dispensed with a Rollenrichtmaschine or other measures in front of a split, engageable Längsfeldinduktionsheizung if at each skafteftten not to be heated tape head of the inductor gap is increased.

FIG. 3 It shows an upper induction coil 110, which is arranged above the metal strip 200 to be heated, and a lower induction coil 120, which is arranged below the metal strip to be heated, opposite the upper induction coil 110. The two induction coils 110, 120 are fed by a power supply device 130 with electrical energy, more precisely, with out-of-phase electrical currents. Due to this operation of the upper and lower induction coil with antiphase currents, the inductor 100 acts as a longitudinal field inductor 170. In contrast to traditional longitudinal field inductors, the in FIG. 3 described design of Längsfeldinduktors the advantage that the upper induction coil 110 and the lower induction coil 120 are independently vertically displaceable, so that the distance of the upper induction coil to the top of the metal strip 200 and the distance of the lower induction coil 120 to the underside of the metal strip 200 individually in the desired Way and depending on the thickness of the metal strip 200 can be adjusted.

FIG. 4 illustrates that the upper induction coil 110 is typically associated with an upper capacitor 115, wherein the upper induction coil and the upper capacitor 115 are connected to an upper part of the resonant circuit. Similarly, the lower inductor is connected to an associated capacitor 125 to a lower resonant circuit. The upper resonant circuit is associated with an upper longitudinal field inductor 140 for moving the upper resonant circuit or at least the upper coil 110 perpendicular to the plane formed by the metal strip 200. Analogously, a lower Längsfeldinduktor-displacement device 150 is assigned to the lower part of the resonant circuit for moving the lower resonant circuit or at least the lower induction coil 120 perpendicular to the plane spanned by the metal strip 200 level.

The upper and lower induction coils 110, 120 of the longitudinal field inductor 100, 170 or their housings are as in FIG FIG. 4 shown, C-shaped for transverse movement of the inductor by means of the Induktorwagens 142 or a similar Querverfahrmechanismus in or out of the line of the metal strip 200. The line corresponds to the material flow direction R, which in FIG. 4 directed into or out of the drawing plane.

As mentioned above with reference to FIG. 1 In addition to the at least one longitudinal field inductor 100, 170 between the roughing stand 120 and the first stand F1 of the finishing train 440, the rolling mill 400 may include a transverse field inductor 180. The Querfeldinduktor is in a known manner, as in the prior art with reference to FIG. 9 described, trained. The arrangement described above with respect to the Längsfeldinduktor 100, 170 according to FIG. 4 Similarly, the Querfeldinduktor 180. Concretely, the Querfeldinduktor 180 comprises a top of the metal strip 200 associated upper Querfeldinduktorspule 182 and one of the underside of the metal strip 200 associated lower Querfeldinduktorspule 184. The Querfeldinduktorspulen 182, 184 capacitors 115, 125 may be assigned, which form part resonant circuits together with the inductor coils. An upper transverse field inductor traverse device 186 is provided for moving the upper cross field inductor coil 182 and the upper transverse field inductor partial resonant circuit, respectively, perpendicular to the plane defined by the metal strip. Likewise, a lower transverse field inductor shuttle 188 is provided for moving the lower transverse field inductor coil 184 and the lower transverse field inductor partial resonant circuit, respectively, also perpendicular to the plane defined by the metal strip.

The upper and lower transverse field inductor traversers 186, 188 and / or the upper and lower longitudinal field inductor traversers 140, 150 may form a structural unit. This structural unit is preferably associated with an inductor carriage 142 for moving the longitudinal field inductor and / or the transverse field inductor transversely to the longitudinal direction of the metal strip out of the line of the metal strip or into the line of the metal strip 200.

The Querfeldinduktor-displacement devices 186, 188 and / or the Längsfeldinduktor-displacement devices 140, 150 or the Induktorwagen 142 are controlled by a control device 187; please refer FIG. 4 ,

FIG. 5 shows a top view of the metal strip 200. It can be seen a temperature measuring device 190 and optionally 550 for detecting the distribution of the temperature over its width. The temperature measuring device 190 is preferably arranged behind the last rolling stand F _{N of} the finishing train 440. The measured temperature distribution is supplied as an input to the controller 187 to be responsive to the temperature distribution, the upper and / or the lower Längsfeldinduktor-displacement device 140, 150 and / or the upper and / or lower Querfeldinduktor-displacement device 186, 188 and / or the Induktorwagen 142 suitably controls. Suitable in this case means that the inductor 100, ie the longitudinal field inductor 170 or the Querfeldinduktor 180 is positioned in response to the necessary energy input and the measured temperature distribution that the difference between the measured temperature distribution behind the finishing train 440 and a predetermined Target temperature distribution at the same position over the material width is minimal. By taking into account the effects on the inductors and in the rolling train, the properties of the finished product over the width can be optimally adjusted.

For the appropriate control of the inductors (powers, Induktoranstellungen) using a process model also optionally the input temperature distribution 550 is taken into account.

Furthermore, a sensor device 195 may be provided for detecting an irregularity in the metal strip 200, such as a ski z. B. at the head of the metal strip, a wave or a bow in the metal strip or a other disturbance of the rolling process. The sensor device 187 is then designed in response to a signal of the sensor device, which represents the irregularity, for driving the Längsfeldinduktor-displacement devices 140, 150 and / or the Querfeldinduktor-displacement devices 186, 188 or the Induktorwagens 142 such that the distance d of the inductor coils is changed suitably from the top / bottom of the metal strip in the region of the irregularity and / or the inductors are moved out of the line of the metal strip out.

Furthermore, at least one touch sensor 198 may be provided, e.g. In the form of a motion sensor or an accelerometer for detecting contact of the longitudinal field inductor 170 and / or the transverse field inductor 180 with the metal strip 200. The controller 187 is then configured to drive the in response to a signal from the touch sensor representing the eventual touch Längsfeldinduktor-displacement devices 140, 150 and / or the Querfeldinduktor-displacement devices 186, 188 and / or the Induktorwagens 142 such that the Längsfeldinduktor 100, 170 and / or Querfeldinduktor 180 when touching the metal strip 200 in the thickness direction opened and / or laterally from the Line is driven out.

FIG. 6 It comprises a casting machine 300 according to the invention for producing the metal strip 200 and the above-described, the casting machine 300 in the material flow direction R downstream rolling mill 400. According to a first embodiment, between the casting machine 300 and the rolling mill 400 is a furnace 350 switched. The rolling mill 400 has, as already described above, a longitudinal field inductor 170 and / or a transverse field inductor 180 according to the invention between the at least one roughing stand 420 and the first stand F1 of the finishing train 440.

Between the furnace 350 and the at least one roughing stand 420, a further longitudinal field inductor 170 and / or the transverse field inductor 180 may be connected.

Concretely, the further longitudinal field inductor 170 may also be connected between the furnace 350 and the roughing stand, and the transverse field inductor 180 may be connected between individual ones of the finishing rolling stands of the finishing train.

FIG. 7 illustrates the preferred application of the invention divided Längsfeldinduktors without frame structure, ie with individually perpendicular to the level of the metal strip engagable upper and lower induction coil. The dashed lines show the course of the electrical efficiency for a Längsfeldinduktor closed inductor frame whose upper and lower induction coil are not adaptable to the respective thickness ratios of the metal strip. The dotted line shows the course of the efficiency for a Querfeldinduktor and the two solid lines show the course of the electrical efficiency as a function of the strip thickness for a Längsfeldinduktor with advantageously individually adjustable upper and / or lower induction coil as a function of strip thickness. Both the dashed lines for the closed longitudinal field inductor and the solid lines for the split longitudinal field inductor are each given for two different frequencies f _j f _i , f _m and f _n , with the different frequencies chosen optimally with respect to the band thickness ranges of use become. In general, the diagram according to FIG FIG. 7 in that the electrical efficiency is particularly high when using transverse field inductors (dot-dashed line) for strip thicknesses <6 mm. In contrast, for strip thicknesses of z. B. 100 mm, the efficiency is particularly large when using Längsfeldinduktoren, in which case it does not matter whether divided engageable Längsfeldinduktoren or closed Längsfeldinduktoren be used. Independently of this it can be seen that for average strip thicknesses between approx. 6 and approx. B. 100 mm the use of

Längsfeldinduktoren with individually engageable upper and lower induction coil (solid lines) is electrically particularly effective; see the vertically hatched area in FIG. 7 ,

Finally, the invention relates to a method for producing a metal strip with a rolling mill 400 according to the invention or a casting-rolling plant 500 according to the invention. The rolling mill and the casting-rolling plant each comprise at least one longitudinal field inductor 170 and optionally additionally at least one transverse field inductor 180 According to a method, the distance d of the upper and lower adjustable inductor coils of the longitudinal field inductor or the transverse field inductor during the rolling of the fillet of the metal strip 200 is set to a suitable operating distance d <60 mm, depending on the respective thickness of the metal strip. This operating distance is preferably kept constant during the rolling of the fillet at a distance of d <20 mm. Advantageously, a minimum distance of 15 mm has been shown.

The upper and / or the lower adjustable inductor coil of Längsfeldinduktors and optionally also the Querfeldinduktors are moved during the threading process of the head of the metal strip in a rolling mill either to a predefined safety distance or moved to outside the band line. Only after completion of the threading process, the induction coils, synonymous with inductor coils, set to the appropriate operating distance. Only when the respective desired operating distance d is reached or comes close to the metal strip, the inductors 100, 170, 180 are activated, that is acted upon by electrical energy. The energy supply device 130 according to the invention is designed to supply all electronic components, ie in particular the induction coils and the displacement devices and the inductor carriage with electrical energy.

The upper and lower induction coils 110, 120, 184, 186 of the longitudinal field inductor 170 and / or the Querfeldinduktors 180 are raised again to the predefined safety distance z. B. just before the end of the metal strip 200 leaves a roll stand before the respective Längsfeldinduktor or Querfeldinduktor or when a previously existing strip tension is broken down or when a Walzunfall had happened or in another disturbance of the mass flow. As an alternative to driving up to the predefined safety distance, the induction coils can also be moved out of the line of the metal strip.

The casting-rolling plant is preferably operated in a continuous mode and / or in a semi-endless mode. A definition of "endless mode" is given above in the general part of the description. The term "semi-continuous mode" means casting a long slab that finds room in the oven 350, and then rolling and separating the slivers in front of the coiler to some coils. Depending on the length of the oven z. B. 5 consecutive slabs continuously rolled successively (similar to endless) and only behind the finishing line with the scissors divided and z. B. 5 single coils wound.

LIST OF REFERENCE NUMBERS

100

inductor

110

upper longitudinal field inductor coil

115

upper capacitors

120

lower longitudinal field inductor coil

125

lower capacitors

130

Power supply means

140

upper Längsfeldinduktor-displacement device

142

Induktorwagen

150

lower Längsfeldinduktor-displacement device

170

longitudinal field

180

Querfeldinduktor

182

upper cross field inductor coil

184

lower transverse field inductor coil

186

upper cross field inductor traversing device

187

control device

188

Lower transverse field inductor traversing device

190

Temperature-measuring device

195

sensor device

198

touch sensor

200

metal band

300

casting machine

350

oven

400

rolling plant

420

roughing

430

separator

440

Finishing mill

450

cooling device

460

coiler

500

Casting and rolling plant

550

Temperature-measuring device

F ₁

Second rolling mill = first finishing mill

F ₁ -F _n :

Finishing stand

d

distance

R

Material flow direction

AH

Variation of the metal strip thickness

Claims (28)

Rolling mill (400) with
at least a first (420) and a second rolling stand; at least one inductor (100) disposed between the first and second rolling stands for heating a metal strip (200) moved by the inductor, the inductor including an upper induction coil (110) disposed above the metal strip (200) to be heated, and a lower induction coil (120) disposed below the metal strip to be heated opposite the upper induction coil; and
a power supply means (130) for supplying the upper and lower induction coils with electric power;
characterized,
in that the first rolling stand is at least one roughing stand (420) and the second rolling stand (F1) is a first rolling stand from a plurality of rolling stands of a finishing train;
in that the energy supply device (130) is designed to operate the upper and the lower induction coil (110, 120) of the inductor (100) with opposite-phase electrical currents and thus the inductor as a longitudinal field inductor (170);
in that an upper longitudinal field inductor movement device (140) is provided for moving the upper induction coil (110) perpendicular to the upper side the metal strip (200) and / or a lower Längsfeldinduktor-displacement device (150) for moving the lower induction coil (120) perpendicular to the underside of the metal strip (200); and
that the distance (d) of the upper induction coil (110) from the top of the metal strip and / or the distance of the lower induction coil (120) from the underside of the metal strip in a working position d <60 mm, preferably d is d <20mm. Rolling mill (400) according to claim 1,
characterized,
in that the energy supply device (130) has upper capacitors (115), which are connected to the upper induction coil (110) to form an upper part of the resonant circuit, and lower capacitors (125), which are connected to the lower induction coil (120) to a lower resonant circuit ; and
in that the upper longitudinal field inductor traversing device (140) is designed to move the upper partoscopic circuit perpendicular to the upper side of the metal strip and / or that the lower longitudinal field inductor traverse device (150) is designed to move the lower induction coil (120) perpendicular to the lower side of the metal strip (200 ). Rolling mill (400) according to one of the preceding claims,
characterized in that
the upper and lower induction coils (110, 120) of the longitudinal field inductor (100) or their housings are C-shaped to transverse the longitudinal field inductor into and out of the line of the metal strip (200). Rolling mill (400) according to one of the preceding claims,
characterized,
that the upper and the lower induction coil (110, 120) each consist of a single turn or from a plurality of parallel and preferably cross-connected partial windings are formed. Rolling plant according to claim 2,
characterized,
in that the energy supply device (130) is designed to operate the induction coils (110, 120) and the partial resonant circuits, depending on the thickness of the metal strip, with current or voltage frequencies between 2 kHz and 30 kHz. Rolling plant according to claim 4 or 5,
characterized,
that the number of partial turns per induction coil - depending on frequency - is between 3 and 15. Rolling mill (400) according to one of the preceding claims, further characterized by
at least one transverse field inductor (180) which is operable in addition to the at least one Längsfeldinduktor in the rolling mill. Rolling mill (400) according to claim 7,
characterized,
in that the transverse field inductor (180) comprises an upper transverse field inductor resonant circuit associated with the upper side of the metal strip, comprising a capacitor (115) and a transverse field inductor coil (182) and a lower transverse field inductor resonant circuit associated with the underside of the metal strip, comprising a capacitor 125 and a transverse field inductor coil (184) ; and
in that an upper transverse-field-inductor-displacement device (186) is provided for moving the upper transverse-field-inductor partial resonance circuit and a lower Querfeldinduktor-displacement device (188) is provided for moving the lower transverse field inductor resonant circuit, each perpendicular to the plane of the metal strip (200) plane. Rolling mill (400) according to claim 8,
characterized,
in that the upper and lower transverse field inductor travel devices (186, 188) and / or the longitudinal and lower longitudinal field inductor travel devices (140, 150) form a structural unit. Rolling mill (400) according to claim 9,
characterized,
in that the structural unit has an inductor carriage (142) for moving the longitudinal field inductor and / or the transverse field inductor transversely to the longitudinal direction of the metal strip out of the line or into the line of the metal strip (200). Rolling mill (400) according to one of the preceding claims,
characterized in that
a control device (187) is provided for driving the upper and / or lower Querfeldinduktor-displacement device (186, 188) and / or the upper and / or lower Längsfeldinduktor-displacement device (140, 150) or the Induktorwagens (142). Rolling plant (400) according to claim 11,
characterized,
that a temperature measuring device (190) is provided for detecting the distribution of the temperature of the metal strip over its width; that the temperature-measuring device is preferably arranged behind the last roll stand of the finishing train; and
in that the control device (187) is designed to control the upper and / or lower Längsfeldinduktor-displacement device (140, 150) and / or the upper and / or lower Querfeldinduktor-displacement device (186, 188) and / or the Induktorwagens (142) so in that the longitudinal field inductor (100), the further longitudinal field inductor (170) or transverse field inductor (180) is positionable in response to the measured temperature distribution such that the difference between the measured temperature distribution and a predetermined desired temperature distribution over the metal bandwidth becomes minimal. Rolling mill (400) according to claim 11 or 12,
characterized,
that a sensor means (195) is provided for detecting an irregularity in the metal strip, such as a ski at the head of the metal strip, a wave or arc in the metal strip, or any other disturbance of the rolling process; and
in that the control device (187) is designed to control the upper and / or lower Längsfeldinduktor-displacement device (140, 150) and / or the upper and / or lower Querfeldinduktor-displacement device (186, 188) and / or the Induktorwagens (142) such in that the distance (d) of the inductor coils from the top / bottom of the metal strip in the region of the irregularity is suitably changed or / and the inductors are moved out of the line of the metal strip. Rolling plant (400) according to one of claims 11 to 13,
characterized in that
at least one touch sensor (198) is provided, for example in the form of a motion sensor or an accelerometer, for detecting contact of the longitudinal field inductor (170) and / or the transverse field inductor (180) with the metal strip 200; and
the control device (187) is designed to control the upper and / or lower Längsfeldinduktor-displacement device (140, 150) and / or the upper and / or lower Querfeldinduktor-displacement device (186, 188) and / or the Induktorwagens (142) such, in that the longitudinal field inductor (100) or / and the transverse field inductor (180) is opened in the thickness direction when the metal strip (200) is touched and / or is moved laterally out of the line. Rolling mill (400) according to one of the preceding claims,
characterized,
in that a further longitudinal field inductor (170) and / or the transverse field inductor (180) is connected between individual rolling stands of the finishing train. Casting-rolling plant (500) with
a casting machine (300) for producing a metal strip (200); marked by
one of the casting machine in the direction of material flow downstream rolling mill (400) according to one of the preceding claims 1 to 15. Casting-rolling plant (500) according to claim 16,
characterized,
in that a furnace (350) is connected between the casting machine (300) and the rolling train (400); and
in that at least one further longitudinal field inductor (170) and / or the at least one transverse field inductor (180) is connected between the furnace (350) and the roughing stand (420). Casting-rolling plant (500) according to claim 17,
characterized,
in that the divided at least one additional longitudinal field inductor (170) which can be set in the thickness direction of the metal strip is connected between the furnace (350) and the roughing stand and the at least one transverse field inductor (180) between individual ones of the finishing rolling stands (440-n). Method for producing a metal strip with a rolling mill (400)
according to one of claims 1-15 or a casting / rolling plant (500) according to one of claims 16 to 18, with a longitudinal field inductor (170) and optionally additionally a transverse field inductor (180).
characterized in that
the distance d of the upper and / or lower adjustable inductor coils of the longitudinal field inductor or the transverse field inductor during rolling of the fillet of the metal strip (200) is set to a suitable operating distance d <60mm depending on the thickness of the metal strip. Method according to claim 19
characterized
that the distance (d) during the rolling of the fillet is kept constant. Method according to claim 19 or 20,
characterized,
that the suitable operating distance of the inductors to the metal strip (200) during the rolling of the fillet of the metal strip is set to a value d <20 mm. Method according to one of claims 19 to 21,
characterized,
in that the upper and / or the lower adjustable induction coils (110, 120, 182, 184) of the Längsfeldinduktors (100) and possibly also the Querfeldinduktors (180) are driven during the threading of the head of the metal strip in a rolling mill either to a predefined safety distance or moved to outside the band line; and
that the upper and / or lower induction coils (110, 120, 182, 184) of the Längsfeldinduktors (100) and possibly also the Querfeldinduktors (180) only after completion of the threading or after passing through the tape head - if necessary, only in the line of Retracted metal band - and adjusted to the appropriate operating distance. Method according to one of claims 19 to 22,
characterized,
that the inductors (100, 170, 180) are activated only when they are at the operating distance to the metal strip (200). Method according to one of claims 19 to 23,
characterized,
in that the upper and lower induction coils (110, 120, 184, 186) of the longitudinal field inductor (100, 170) and / or the transverse field inductor (180) are moved back to the predefined safety distance, or the inductors are moved out of the line of the metal strip, for Example just before the end of the metal strip leaves a rolling stand in front of the respective longitudinal inductor or Querfeldinduktor or a previously existing strip tension is broken down or in the event of a Walzunfall or other disturbance of the mass flow. Method according to one of claims 19 to 24,
characterized,
that the casting-rolling plant (500) in a continuous mode and / or semi-endless mode is operated. Method according to one of claims 19 to 25,
characterized,
that the split engagable in the thickness direction of the metal strip longitudinal field inductor (100, 170) is preferably used from a metal strip thickness ≥ 6 mm. Method according to one of claims 19-26,
characterized in that
the upper and lower transverse field inductor traversers (186, 188) and / or the longitudinal and lower longitudinal field inductor traversers (140, 150) advantageously for maximizing heating efficiency on the metal strip by minimizing the inductor distance d from the metal strip and avoiding contact with the metal strip Opening of the inductor can be used. Use of the longitudinal field inductor (170) in the rolling mill after a
of claims 1-15;
characterized in that
the split longitudinal field inductor (100, 170) which can be set in the thickness direction of the metal strip is used for metal strips with thickness variations in the region of the inductors of ΔH ≥ 6 mm or particularly preferably ΔH ≥ 15 mm.

Images