Situation-dependent metal strand separation

Abstract

The present invention relates to a continuous casting and rolling system (10) and to a method (200) for the continuous production of hot strip (12). The following are provided: i) a casting machine (20) for casting (S1) a metal strand (14); ii) a first separating device (30) for separating (Y3; Z4) the cast metal strand (14); iii) a descaling device (40) for descaling the cast metal strand (14); iv) a single roll stand group (50) for rolling (S3) the cast or descaled metal strand (14) to form a hot strip (12); v) a cooling section (60) for cooling (S4) the rolled hot strip (12) to a coiling temperature; vi) at least two coilers (80, 82) for coiling (S5) the cooled hot strip (12); and vii) a second separating device (70), which is arranged between the cooling section (60) and the at least two coilers (80, 82), for separating (S6) the coiled hot strip (12) from the subsequent hot strip (12).

Description

[0001] Description

[0002] Situation-dependent metal strand separation

[0003] field of technology

[0004] The present invention relates to a casting and rolling plant and a method for the continuous production of hot strip.

[0005] State of the art

[0006] For the production of hot-rolled metal strip, i.e., hot-rolled metal strip, so-called combined casting and rolling plants, or casting and rolling plants for short, are often used. In these plants, the casting process, in which a metal strand is cast from liquid metal, is linked to the rolling process. In contrast to batch operation, in which individual slabs are cut from the metal strand and then rolled, continuous operation involves a continuous mass flow between a casting machine and one or more rolling stand groups, for example, a first rolling stand group, also known as a "roughing mill," and a second rolling stand group, also known as a "finishing mill."

[0007] With a view to achieving the most resource-efficient and cost-effective hot strip production possible, it is particularly advantageous to utilize as much of the casting heat still present in the cast metal strand as possible during rolling. Such an approach can be realized, for example, by providing only one rolling stand group that rolls the cast strand to the target thickness, i.e., the final product, immediately after it leaves the casting machine. In this case, the casting heat may be sufficient to carry out the desired rolling process without the need for reheating the metal strand. A casting-rolling plant configured in this way is known, for example, from EP 3 558 563 A1.

[0008] Summary of the invention

[0009] Against this background, it is an object of the present invention to further improve the continuous production of hot strip, in particular to enable a flexible and low-cost reaction to different operating situations and / or to facilitate and / or efficiently design the change between different operating states of a casting and rolling plant.

[0010] This object is achieved by a casting-rolling plant and a method for the continuous production of hot strip according to the independent claims. Preferred embodiments are the subject of the dependent claims and the following description.

[0011] According to a first aspect of the invention, a casting and rolling plant for the continuous production of hot strip comprises: i) a casting machine for casting a metal strand; ii) a first separating device for separating the cast metal strand; iii) a first temperature measuring device for measuring a strand temperature of the cast metal strand at the exit of the casting machine; iv) a speed measuring device for measuring the strand speed at the exit of the casting machine; v) a descaling device for descaling the cast metal strand; vi) a single rolling stand group for rolling the cast or descaled metal strand into a hot strip; vii) a cooling section for cooling the rolled hot strip to a coiling temperature; viii) a second temperature measuring device for measuring a final rolling temperature of the rolled hot strip at the exit of the rolling stand group; viiii) at least two coils for coiling the cooled hot strip;x) a second separating device arranged between the cooling section and the at least two coilers for separating the coiled hot strip from the subsequent hot strip; xi) and a plant control system for actuating the first separating device for separating the cast metal strand, based on the modeled or measured final rolling temperature of the hot strip.

[0012] The aforementioned components are expediently arranged in the specified order. The rolling stand group, the cooling section, the second separating device, and the at least two coilers are preferably arranged directly one after the other. This means that no further components for handling the rolled hot strip are provided between them.

[0013] Continuous production in the sense of the present invention is preferably a substantially uninterrupted production of hot strip during a casting sequence, ie between a start-up or a start of hot strip production and a shut-down or end of hot strip production.

[0014] Hot strip in the sense of the present invention is preferably a hot-rolled metal strip with a thickness of 1 mm to 25 mm.

[0015] A first temperature measuring device measures the temperature of the cast metal strand at the exit of the casting machine. A speed measuring device measures the strand speed at the exit of the casting machine.

[0016] A second temperature measuring device measures the final rolling temperature of the rolled hot strip at the exit of the rolling stand group. A transport direction within the meaning of the invention is preferably a direction in which the cast metal strand or the rolled hot strip is transported through the casting and rolling mill. Terms used in connection with the arrangement of components of the casting and rolling mill relative to one another, such as "before" or "upstream," "behind" or "downstream," and "between," expediently refer to this transport direction, unless otherwise stated.

[0017] Using a modeling unit for calculating the final rolling temperature of the hot strip at the exit of the rolling stand group based on the measured and / or modeled average strand temperature and the specific mass flow of the metal strand, it is possible to determine the expected final rolling temperature at the exit of the last stand of the rolling stand group. The final rolling temperature is a temperature required to adjust the microstructure and thus the mechanical properties of the rolled strip. The specific mass flow during rolling refers to the amount of material that flows through the casting and rolling mill per unit of time and per meter of width. The average strand temperature can be calculated based on the measured temperature of the metal strand or using a conventional modeling approach.

[0018] One aspect of the invention is based on the approach of optimally utilizing the casting heat (still) contained in the metal strand after casting by means of a casting machine during a rolling process by means of a rolling stand group arranged essentially immediately downstream of the casting machine, but being able to cut the metal strand if necessary before it enters the rolling stand group. For this purpose, a casting and rolling plant is proposed with a first cutting device arranged between the casting machine and a single rolling stand group. The first cutting device allows the mass flow between the casting machine and the rolling stand group to be interrupted if necessary, for example in the event of a malfunction or when shutting down hot strip production, i.e. when a casting sequence is terminated.In addition, the ability to separate part or several pieces of the cast metal strand before the rolling process can also be used, for example, for taking samples or to significantly simplify the ramp-up of hot strip production, i.e. the start of a casting sequence.

[0019] For the production of hot strip, it is expedient if the casting machine is designed to cast a metal strand with a thickness of 80 mm to 240 mm and a width of 500 mm to 2500 mm. For casting thin metal strands, for example up to 130 mm, the casting machine can have a funnel-shaped mold, i.e. a mold with copper plates adjusted or angled relative to one another. For casting thick metal strands, for example from 130 mm, a mold with plates aligned parallel to one another can be provided. Since high transport and rolling speeds are usually prevalent in the continuous production of hot strip, it is expedient to provide a casting machine designed for casting at high specific mass flows.The casting machine may, for example, be designed to cast at mass flows of 3.5 tonnes per minute and meter width or more, preferably at 4 tonnes per minute and meter width or more, in particular at up to 5 tonnes per minute and meter width.

[0020] The casting-rolling plant may additionally include a lifting system for withdrawing a dummy bar from the casting machine. This lifting system is conveniently located between the casting machine and the first separating device.

[0021] The first cutting device for cutting the cast metal strand is actuated by a plant control system, whereby a decision is made on the basis of a modeled or measured end-of-rolling temperature of the hot strip as to whether the cast metal strand is to be cut or whether the metal strand is to be rolled into a hot strip in continuous production. In the event that the calculated end-of-rolling temperature or the measured end-of-rolling temperature does not reach or no longer reaches a specified target end-of-rolling temperature, e.g. because the strand temperature and / or the strand speed and thus the specific mass flow are too low, the metal strand is cut and the continuous rolling of the rolled strip is stopped. This makes it possible to determine the optimal time for cutting the metal strand and thus the time for starting or ending continuous production of the metal strip for all operating states of the casting and rolling plant, such as at the start or end of a casting sequence or in the event of a malfunction.

[0022] Alternatively or additionally, the casting-rolling mill can also have an inductive heating arrangement for heating the cast or descaled metal strand. This heating arrangement is expediently arranged upstream of the descaling device or between the descaling device and the rolling stand group. An inductive heating arrangement is a heating arrangement that is operated exclusively electrically. Thanks to inductive heating, the heating arrangement can be particularly compact. Such a heating arrangement can, for example, have one or more induction modules for inductively heating the, optionally descaled, metal strand before rolling and / or strand edge heaters.The heating arrangement can, for example, be switched on to increase the temperature of the metal strand to a predetermined rolling temperature, even at low casting speeds, such as those encountered during ramp-up or ramp-down of hot strip production, or - since heat can still be lost until the first or last roll stand in the roll stand group is reached - to a temperature suitable for reaching the predetermined rolling temperature or to reduce the risk of edge cracks. Even better temperature control during the rolling process can be achieved by arranging individual induction modules and / or cooling modules between individual roll stands in the roll stand group. This enables individual setting of rolling temperatures at the individual roll stands and thermomechanical rolling. This makes it possible to produce hot strip of particularly high quality, if necessary.

[0023] Alternatively or additionally, the casting-rolling mill can have a scarfing device for scarfing the cast metal strand. The scarfing device is expediently arranged between the casting machine and the first separating device. Alternatively, the scarfing device can be arranged between the first separating device and the descaling device, or optionally also between the first separating device and the inductive heating arrangement. For very high quality requirements for the produced hot strip, for example, surface-critical hot strip grades, at least part of the strand surface can be removed using the scarfing device. Since scarfing of the cast metal strand is usually not necessary for all grades, it is expedient to design the scarfing device as an extendable device.

[0024] In addition to the second separating device, the casting-rolling mill can have a third separating device for separating the coiled hot strip from the subsequent hot strip. The third separating device is preferably arranged upstream of the second separating device and is preferably (likewise) designed as a drum shear. The second and third separating devices can be designed to separate strips of different thicknesses. This allows a larger thickness range to be covered. For example, the second separating device can be designed to separate hot strips with a thickness of 1 mm to 12 mm, while the third separating device can be designed to separate hot strips with a thickness of 12 mm to 25 mm.

[0025] Alternatively or additionally, the casting-rolling mill may have a discharge device in the area of ​​the cooling section for discharging slabs or plates before they reach the at least two coilers. This also allows unrolled strand sections, which have been separated from the cast metal strand by the first separating device and pass through the rolling stand group unrolled, to be discharged from the casting-rolling mill.

[0026] Preferred embodiments of the invention and their further developments are described below. These embodiments can be combined with each other and with the aspects of the invention described below, unless expressly excluded.

[0027] In a preferred embodiment, a removal system is provided for removing strand pieces separated from the cast metal strand by means of the first separation device from a transport path defined between the casting machine and the rolling stand group. With such a removal system, samples of the cast strand can be taken, as will be described in more detail below. Furthermore, the material flow can be diverted with the removal system in the event of a malfunction. For example, it is conceivable to sequentially separate strand pieces from the metal strand using the first separation device and remove them from the transport path using the removal system, while the malfunction is rectified further downstream, for example in the area of ​​the rolling stand group or the at least two reels. The casting machine can continue to operate or can be shut down in a controlled manner.

[0028] Accordingly, in a further preferred embodiment, the removal system is designed for removing short strand pieces with a maximum length of 3 m or less, preferably 2 m or less, more preferably 1 m or less. The removal system can therefore preferably be designed such that only strand pieces that have a maximum length of at most the stated maximum length can be removed. Such short strand pieces can be removed more easily from the transport path. In addition, the transport path can also be kept short, so that less casting heat is lost during the transport of the cast strand from the first separating device to the rolling stand group.

[0029] In a further preferred embodiment, the first cutting device is designed as a pendulum shear. Consequently, the first cutting device advantageously has blades pivotable with a pendulum, also referred to as upper and lower blades, with which the metal strand can be severed at different pendulum deflections. Thus, when the casting machine is at a standstill, i.e., when the metal strand is stationary, the maximum cutting width of the pendulum shear is defined by the length and the two maximum deflections of the pendulum at which the metal strand can be cut.

[0030] The removal system is therefore preferably designed for removing strand pieces with a length corresponding to the maximum cutting width of the pendulum shears when the casting machine is at a standstill. The removal system can therefore, in particular, remove strand pieces that are cut from the cast metal strand by two cuts of the pendulum shears when the metal strand is at a standstill. In principle, however, the removal system can also remove shorter strand pieces from the transport line. It is equally possible for the removal system to remove longer strand pieces.

[0031] In a further preferred embodiment, the removal system comprises a device for lifting a strand portion separated from the cast metal strand by the first separating device in the region of a base end facing the first separating device. For example, one or more rollers can be provided which, by means of a corresponding actuator, can be moved essentially perpendicular to the transport direction, in particular vertically, to lift the strand portion in the region of its base end. This makes it possible to create space after a first cut in order to subsequently guide longer strand portions separated from the cast metal strand out of the transport path under the raised base end.

[0032] Accordingly, in a further preferred embodiment, the removal system comprises a conveyor device arranged in the transport direction of the metal strand directly behind the first separating device, in particular in the region of the lifting device, for conveying out a strand piece separated from the metal strand by the first separating device. The conveyor device can, for example, be configured to convey such a separated strand piece laterally out of the transport path. This allows the casting machine to continue operating in the event of a malfunction in the area of ​​the rolling stand group or the at least two reels, with the metal strand being cast in the process being sequentially divided into strand pieces, and the strand pieces being conveyed out.

[0033] In a further preferred embodiment, the removal system comprises a collecting container arranged directly below the first separating device for strand pieces separated from the cast metal strand by the first separating device when the casting machine is at a standstill. The separated strand pieces can thus fall into the collecting container. Consequently, an active conveying device for removing the strand pieces when the casting machine is at a standstill and possibly also when the casting machine is in operation is not necessary. However, such a conveying device can be advantageous for removing strand pieces separated from the metal strand in a controlled manner directly behind the first separating device when the casting machine is in operation.

[0034] According to a second aspect of the invention, the method for the continuous production of hot strip, in particular by means of a casting and rolling mill according to the first aspect of the invention, comprises: i) casting a metal strand by means of a casting machine; ii) guiding the cast metal strand past a first separating device and then through a descaling device; iii) rolling the cast metal strand or the metal strand descaled by means of the descaling device into a hot strip in a single rolling stand group; iv) cooling the rolled hot strip to a coiling temperature by means of a cooling section; v) coiling the cooled hot strip by means of at least two coils; vi) separating the coiled hot strip from the subsequent hot strip by means of a second separating device arranged between the cooling section and the at least two coils;vii) modelling a rolling end temperature at the exit of the rolling stand group on the basis of a mean strand temperature measured at the exit of the casting machine and / or a calculated mean strand temperature, a strand speed measured at the exit of the casting machine and taking into account the specific mass flow of the metal strand for the hot strip with a rolling end thickness d; viii) wherein the metal strand is then separated using the first separating device if the calculated rolling end temperature is lower than a target rolling end temperature of the hot strip; ix) or the metal strand is then separated using the first separating device if a rolling end temperature of the hot strip measured at the exit of the rolling stand group falls below a target rolling end temperature.;

[0035] By guiding the cast metal strand past the first separating device, which is expediently located between the casting machine and the rolling stand group, the metal strand can be separated as needed, for example, in the event of a malfunction in the rolling stand group or the at least two coilers. Furthermore, it allows the metal strand to be separated before entering the rolling stand group, to separate non-rollable sections from the metal strand during ramp-up or ramp-down of hot strip production, and / or to control the mass flow from the casting machine independently of the mass flow into the rolling stand group.

[0036] Accordingly, in a preferred embodiment, during the ramp-up and / or ramp-down of hot strip production and / or in the event of a malfunction, particularly in the area of ​​the rolling stand group or the at least two coilers, the cast metal strand is separated by means of the first separating device. This allows the mass flow between the casting machine and the rolling stand group to be interrupted. The casting machine can therefore continue to operate while the malfunction is rectified, or can be shut down in a controlled manner. It is also possible to interrupt the mass flow at least briefly if the casting speed is too low for reliable rolling and / or if a short strand section is to be taken from the metal strand as a sample.

[0037] Using a modeled end-roll temperature at the exit of the rolling stand group based on an average strand temperature measured and / or calculated at the exit of the casting machine, a strand speed measured at the exit of the casting machine, and taking into account the specific mass flow of the metal strand for the hot strip with a final rolling thickness d, a decision can be made as to whether the metal strand is to be separated using the first separating device. This is the case, for example, if the calculated end-roll temperature is lower than a target end-roll temperature of the hot strip or if a end-roll temperature of the hot strip measured at the exit of the rolling stand group falls below a target end-roll temperature. Calculation methods known to those skilled in the art should be used to calculate the average strand temperature.

[0038] This procedure allows the optimal time for starting or ending continuous rolling of the hot strip to be determined. If, at the beginning of a casting sequence, the strand temperature and strand speed at the casting machine exit are sufficiently high, which indicates a sufficiently high final rolling temperature for the hot strip at the exit of the rolling stand group, continuous rolling begins. Conversely, in the event of a malfunction in the casting system, in the rolling stand group, or at the end of a casting sequence, continuous rolling is terminated by cutting the metal strand.

[0039] In a further preferred embodiment, during the ramp-up or ramp-down of hot strip production, the cast metal strand is cut at least once as soon as a predetermined rolling criterion is met during the ramp-up of hot strip production or as soon as this predetermined rolling criterion is no longer met during the ramp-down of hot strip production. The metal strand can therefore be cut, for example, in particular several times, until the predetermined rolling criterion is met or, from the point in time at which the predetermined rolling criterion is no longer met, in particular several times. The rolling criterion can, for example, relate to a stability of the casting process and / or a temperature of the cast metal strand.For example, the metal strand can be severed if the strand temperature drops below a predetermined rolling temperature due to a casting speed that was initially too low or reduced at the end of the casting sequence when entering or leaving the rolling stand group. This can prevent the rolling process from starting or the casting machine and the rolling stand group from being coupled before a stable casting process or a strand temperature sufficient for further processing has been established. Accordingly, it can be avoided that the casting machine and the rolling stand group remain coupled for too long.

[0040] Conveniently, the fulfillment of the rolling criterion is monitored, preferably essentially continuously. For this purpose, one or more operating parameters of the casting-rolling plant and / or one or more process parameters of the casting process can be determined, for example, by sensory means and / or modeling.

[0041] Accordingly, in a further preferred embodiment, the metal strand is expediently separated by the first separating device at least once as soon as the metal strand reaches the predetermined rolling temperature or can be heated to a temperature suitable for reaching the predetermined rolling temperature by means of an inductive heating arrangement arranged, in particular, directly upstream of the rolling stand group. This can be the case, for example, if the casting speed is increased during the ramp-up of hot strip production to such an extent that the metal strand can at least largely retain the casting heat until it reaches the rolling stand group.As a result, the cast metal strand can be separated from a strand portion that has not yet reached or cannot reach the predetermined rolling temperature and is therefore removed, for example, from the transport path defined between the first separating device and the rolling stand group before passing through the rolling stand group. This removal can be carried out, for example, by means of the removal system, wherein, if necessary, the strand portion is successively divided into several short strand pieces by means of the first separating device. These strand pieces can then be removed individually, for example, by being conveyed out laterally by the conveying device and / or dropped into the collecting container.

[0042] The predetermined rolling temperature can, for example, be a desired final rolling temperature, i.e., the desired strand temperature during the final rolling or upon exiting the last rolling stand of the rolling stand group. The inductive heating arrangement can thus, for example, heat the strand to a temperature sufficiently high that the desired final rolling temperature is achieved despite heat losses during the strand's transport from the heating arrangement to the last rolling stand and the rolling processes taking place in the preceding rolling stands.

[0043] Preferably, the strand temperature is detected, for example, by sensor, modeling, or a combination thereof. For this purpose, the casting-rolling plant, in particular the casting machine, expediently has a corresponding sensor and / or modeling unit as well as a plant control system for controlling the first separating device and, if applicable, the removal system.

[0044] For example, the metal strand can be separated if the strand temperature upon exiting the casting machine has risen to a value that does not fall below the predetermined rolling temperature until it reaches the rolling stand group or leaves the rolling stand group. Alternatively, the metal strand can be separated if the strand temperature upon exiting the casting machine is initially lower than the rolling temperature, but can be increased to the temperature suitable for reaching the rolling temperature with subsequent heating using the inductive heating system. This may depend on the heating capacity of the heating system.

[0045] For example, during the ramp-up of hot strip production, a metal strand with a length of, say, 5 m is typically cast until a strand temperature sufficient for the rolling process has been reached. Accordingly, during the ramp-up of hot strip production, it is preferable to use the first cutting device to cut off a strand section with a length of, say, 5 m and remove it from the transport line, for example, using the removal system. If a heating system is activated during the ramp-up, the length of the strand section to be cut off can be reduced to, say, 2 m.Accordingly, it is preferred, when ramping up hot strip production, to heat the metal strand using the inductive heating arrangement and to use the first cutting device to separate a strand portion with a length of less than 10 m, preferably 5 m or less, particularly preferably 2 m or less, from the cast strand and to remove it from the transport line, for example, using the removal system. In a further preferred embodiment, the metal strand is cut at least once using the first cutting device as soon as the metal strand no longer reaches a predetermined rolling temperature or can no longer be heated to the temperature suitable for reaching the predetermined rolling temperature by means of an inductive heating arrangement arranged, in particular, directly upstream of the rolling stand group.This can be the case, for example, if the casting speed is reduced so much during the shutdown of hot strip production that the metal strand loses at least some of its casting heat until it reaches and / or passes through the rolling stand group. As a result, the cast metal strand can be separated from a strand portion that just reaches or can reach the predetermined rolling temperature and is therefore still rolled into hot strip. Here, too, metal pieces can be separated from the cast metal strand that is no longer to be or cannot be rolled and removed using the removal system.

[0046] Here too, the strand temperature is preferably recorded, for example by sensor, modeling or a combination thereof.

[0047] In a further preferred embodiment, during the ramp-up or ramp-down of hot strip production, the cast metal strand is heated by means of an inductive heating arrangement arranged, in particular, directly upstream of the rolling stand group, to a temperature suitable for reaching the predetermined rolling temperature for the rolling stand group. This heating preferably takes place during the ramp-up of hot strip production until the cast metal strand already contains sufficient heat upon exiting the casting machine to reach the predetermined rolling temperature even without heating by means of the inductive heating arrangement. Alternatively or additionally, this heating takes place during the ramp-down of hot strip production until the heating output of the inductive heating arrangement is no longer sufficient to heat the cast strand to the temperature suitable for reaching the rolling temperature.This can increase the productivity of the casting and rolling plant because a larger portion of the cast strand can be rolled into hot strip.

[0048] In a further preferred embodiment, particularly in the event of a malfunction in the area of ​​the rolling stand group and / or the at least two reels or for sample taking, at least one strand piece is severed from the cast metal strand by means of the first separating device and removed from a transport path defined between the casting machine and the rolling stand group. This removal is expediently carried out by means of the removal system. In the event of a malfunction, the mass flow from the casting machine can thus be diverted, namely out of the casting and rolling mill. As a result, it is not necessary to stop the casting machine, at least not for an extended period of time. Rather, the casting machine can continue to operate essentially without interruption, and cooling of the metal strand in a casting arc of the casting machine can be avoided.In a further preferred embodiment, the operation of the casting machine is briefly interrupted and the cast strand is separated in a front and rear cutting position in the transport direction by means of the first separating device designed as a pendulum shear. The front and rear cutting positions are expediently spaced from one another according to the maximum cutting width of the pendulum shear. A short-term interruption is understood here to be a period of time required to separate the metal strand twice, i.e. to cut the metal strand twice. Preferably, the strand piece produced in this way is removed from the transport section. The strand piece can, for example, fall into a collecting container arranged below the first separating device.This allows a gap to be created with minimal effort between the strand section already engaged in the rolling stand group and the metal strand emerging from the casting machine. The casting machine is then conveniently restarted. This procedure is preferably used in the event of a malfunction. Preferably, after the resumption of casting operations, further strand sections are separated from the cast strand using the first separating device and removed from the transport line. These strand sections can also fall into the collecting container or be removed from the transport line, for example, laterally, using the conveyor device.

[0049] In a further preferred embodiment, the cast metal strand is separated by means of the first separating device and the separated strand part is lifted in the region of a base end facing the first separating device, for example by means of the lifting device. As a result, strand pieces separated from the cast metal strand by means of the first separating device can be removed from the transport path below the raised base end, for example by means of the conveying device. This procedure allows a particularly rapid response to a malfunction, since stopping the casting device is not necessary. However, it is also conceivable to combine the lifting of the base end and the conveying out of strand pieces below the base end with the embodiment described above. For example, the casting operation can initially be briefly stopped in order to cut the initial strand piece from the strand.In addition, the foot end of the (stuck) strand section can be raised to facilitate the cutting and removal of the multiple strand pieces after the resumption of casting operations.

[0050] Short description of the drawings

[0051] The above-described properties, features, and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more readily understood in connection with the following description of an exemplary embodiment, which is explained in more detail in conjunction with the drawings. Figure 1 shows an example of a casting-rolling plant and a method for the continuous production of hot strip;

[0052] Fig. 2 shows an example of a removal system with a collecting container arranged below a first separating device;

[0053] Fig 3 shows an example of a removal system with a lifting device and a conveying device;

[0054] Fig 4 an example of a start-up of a casting and rolling plant; and

[0055] Fig 5 an example of a shutdown of a casting and rolling plant.

[0056] Where appropriate, the same reference numerals are used in the figures for the same or corresponding elements of the invention.

[0057] Description of the embodiments

[0058] FIG 1 shows an example of a casting and rolling plant 10 and a method 200 for the continuous production of hot strip 12. The casting and rolling plant 10 has a casting machine 20 with a mold 22 and a casting arch 24, a first temperature measuring device 21, a speed measuring device 23, a first separating device 30, a modeling device, a plant control system, a descaling device 40, a single rolling stand group 50 with at least one, in the present example six, rolling stands 51, 52, 53, 54, 55, 56, a cooling section 60, a second temperature measuring device 57, a second separating device 70 and at least, in the present example precisely, two coilers 80, 82. In addition, a scarfing device 90 is provided in a transport direction R in front of the first separating device 30 and a removal system 100 with a collecting container 102 is provided in the area of ​​the first separating device 30.An inductive heating arrangement 110 is arranged directly upstream of the descaling device 40. Furthermore, the casting-rolling mill 10 comprises a third separating device 120, which is arranged in the region of the second separating device 70, i.e., between the cooling section 60 and the two coilers 80, 82.

[0059] In a method step S1, the casting machine 20 can cast liquid metal into a metal strand 14 at a rate of preferably more than 3.5 t per minute and meter of width, preferably more than 4 t per minute and meter of width, in particular up to 5 l per minute and meter of width. Such a metal strand 14 expediently has a thickness of between 80 mm and 240 mm and a width of between 500 mm and 2500 mm. With the specific mass flows mentioned and a short transport path S defined between the casting machine 20 and the rolling stand group 50, in particular the first rolling stand 51 of the rolling stand group 50, the casting heat still contained in the cast metal strand 14 upon exiting the casting machine 20 can be retained at least for the most part until it reaches the rolling stand group 50, in particular the first rolling stand 51.Because only a single rolling stand group 50 is provided, this casting heat still contained in the metal strand 14 can then be used for the deformation until the finished hot strip 12 is formed. In normal operation, reheating of the metal strand 14 by the inductive heating arrangement 110 can therefore be dispensed with.

[0060] The transport distance S can be shortened, in particular, because it is free of a slab discharge system and a tunnel kiln. This allows the transport distance S to be shortened to, for example, 15 m or less.

[0061] In a process step S2, the cast metal strand 14 is guided past the first separating device 30 and then through the descaling device 40.

[0062] By means of the first separating device 30, which is designed as a pendulum shear, a strand section 16 can be severed from the metal strand 14 cast by the casting machine 20, thus interrupting the mass flow from the casting machine 20 to the rolling stand group 50. This can be useful, for example, if the casting speed is still very low at the beginning of a casting sequence, i.e. when starting up hot strip production, or is reduced again significantly at the end of the casting sequence, i.e. when shutting down hot strip production. A low casting speed at which such a separation of the cast metal strand 14 is expedient can depend in detail on the thickness and width of the metal strand 14, but is generally below 4 m / min.

[0063] A speed measuring device is provided to record the casting speed, and a first temperature measuring device for measuring a strand temperature is provided to record the temperature of the metal strand at the exit of the casting machine. A modeling unit is provided to calculate a final rolling temperature of the hot strip at the exit of the rolling stand group based on the measured and / or a calculated average strand temperature and on the basis of the specific mass flow of the metal strand. The average strand temperature can be calculated based on the measured temperature of the metal strand or by modeling. A system control system is used to actuate the first cutting device for cutting the cast metal strand based on the modeled or measured final rolling temperature of the hot strip.

[0064] Likewise, separation of the metal strand 14 by the first separation device 30 may be expedient in the event of malfunctions, for example, in the area of ​​the rolling stand group 50 or the two reels 80, 82. In this case, the casting machine 20 can continue to operate, possibly after only a brief interruption, and strand pieces subsequently separated from the cast metal strand 14 can be removed from the transport path S by means of the removal system 100, for example, collected by the collecting container 102 after being separated from the metal strand 14. This can continue until the malfunction has been rectified or the casting process has been terminated in a controlled manner.

[0065] In addition, a sample of the metal strand 14 can be cut out by means of the first cutting device 30 even during ongoing operation, ie during regular hot strip production, and removed from the transport path S by means of the removal system 100.

[0066] In a further process step S3, the metal strand 14 is rolled into hot strip 12 in the rolling stand group 50. For this purpose, the metal strand 14 is expediently brought into engagement with all or at least some of the rolling stands 51-56. The rolling stands 51-56 are preferably designed as four-high stands. However, the first stand 51 can also be designed as a two-high stand. Alternatively or additionally, the last or the last two stands 55, 56 can also be designed as six-high stands.

[0067] In a further process step S4, the hot strip 12 is cooled in a controlled manner on the cooling section 60 down to a coiling temperature. This allows it to be coiled into a coil by means of one of the coilers 80, 82 in a further process step S5. Once the coil has reached a predetermined size or a predetermined weight, in a further process step S6 the coiled hot strip 12, i.e. the coil, is separated from the subsequent hot strip 12 by means of the second separating device 70 or the third separating device 120. Which of the two separating devices 70, 120, which are preferably both designed as drum shears, is used to separate the hot strip 12 can depend on its thickness. The second separating device 70 is expediently set up for separating hot strips 12 with a thickness of 1 mm to 12 mm, preferably 2 mm to 12 mm.The third cutting device 120 is then preferably configured for cutting hot strips 12 with a thickness of 12 mm or more. To minimize the risk of sagging, i.e., the risk of so-called "cobble" formation, for thin strips, the second cutting device 70 is preferably arranged downstream of the third cutting device 120.

[0068] By means of such a casting-rolling mill 10 or such a process 200, hot strip 12 with a thickness between 1 mm and 25 mm can be produced. If necessary, it is also conceivable to produce thicker plates, e.g., between 6 mm and 40 mm, particularly by removing the engagement of the last rolling stands, for example, rolling stands 56 and 55, with the metal strand 14. Such plates can then be transported past the reels 80, 82, as indicated by the dashed lines, and removed from the casting-rolling mill 10 there. FIG 2 shows an example of a removal system 100 with a collecting container 102 arranged below a first separating device 30. The first separating device 30 is designed as a pendulum shear for separating a metal strand 14 and consequently has a pendulum 32 pivotable about a pendulum bearing 34 with a cutting edge 36 arranged above and below the metal strand 14.For reasons of clarity, only the cutting edge 36 above the metal strand 14 is shown in FIG 2. The cutting device 30 can thus cut a stationary cast metal strand 14 at a front cutting position 38a and at a rear cutting position 38b, wherein the terms “front” and “rear” refer to a transport direction R of the metal strand 14 (cf. FIG 1). When cutting at the front cutting position 38a, the pendulum 32 is expediently deflected as far forward as possible, as shown in FIG 2, whereas for cutting at the rear cutting position 38b it is expediently deflected as far rearward as possible, as indicated by the dashed line. As a result, i.e. as a result of the maximum possible deflection forwards and backwards as well as the pendulum length, a maximum cutting width X of the pendulum shears is defined.

[0069] When the metal strand 14 is at a standstill, a strand piece 18 can be cut out of the metal strand 14. This separates the metal strand 14 from a strand part 16, which is located further forward in the transport direction R and is engaged with a rolling stand group (not shown).

[0070] The severed strand section 18 can fall into the collecting container 102 by gravity. Due to the resulting gap between the base end 16a of the strand section 16 and the head end 14a of the metal strand 14, the metal strand 14 can be moved further in the transport direction R. Subsequently, further strand sections 18 can then be severed by means of the first separating device 30. For this purpose, the separating device 30 expediently cuts in the rear cutting position 38b as soon as the head end 14a threatens to meet the base end 16a. In this way, a casting interruption can be avoided in the event of a malfunction in which the strand section 16 can no longer be conveyed further.

[0071] However, with the removal system 100 shown in FIG. 2, a strand section 18 can also be taken as a sample from the hot strip during regular operation of a casting-rolling mill for continuous production. For this purpose, the pendulum shear performs two consecutive cuts on the moving metal strand 14 during continuous operation of the mill.

[0072] FIG 3 shows an example of a removal system 100 with a lifting device 104 and a conveying device 106. The removal system 100 is expediently arranged directly in a transport direction R behind a first separating device 30 for separating a cast metal strand 14. By means of the lifting device 104, for example at least one roller 104a movable perpendicular to the transport direction R by means of an actuator (not shown), such as a hydraulic cylinder, a base end 16a of a strand part 16 severed from the metal strand 14 can be lifted. "Lifting" here means lifting the base end 16a out of the plane in which the metal strand 14 moves or is movable in the transport direction R.

[0073] The conveying device 106 is configured to convey out a strand piece 18 separated from the metal strand 14. The conveying device 106 may, for example, comprise rollers 106a, by means of which the strand piece 18 can be conveyed out laterally, i.e., transversely to the transport direction R or perpendicular to the plane of the figure. In addition, the conveying device 106 preferably comprises a pushing device (not shown), also referred to as a "pusher," for pushing the strand piece 18 laterally transversely to the transport direction R. Alternatively, the rollers 106a may be motor-driven.

[0074] By raising the base end 16a, the metal strand 14 can continue to move in the transport direction R even when the strand section 16 is at a standstill, for example because a malfunction has occurred in a rolling stand (not shown) that has engaged the strand section 16. A head end 14a of the metal strand 14 slides under the raised base end 16a. The strand section 18 can then be severed and conveyed out so that the resulting new head end 14a of the metal strand 14 can also be pushed under the raised base end 16a. In this way, further strand sections 18 can be severed and conveyed out in succession. This procedure can be maintained until the malfunction has been rectified or a casting machine producing the metal strand 14 has been shut down in a controlled manner.

[0075] FIG 4 shows an example of a start-up Y of a casting and rolling plant.

[0076] First, in step Y1, the casting machine's mold is filled with liquid metal, and a cold strand is conveyed through the casting arch and, if necessary, through other horizontal segments of the casting machine. It is then withdrawn from the casting arch, for example, using a suitable elevator system. The liquid metal can flow in and solidifies into a metal strand before exiting the casting machine.

[0077] To stabilize the metal strand during casting, for example to prevent the still liquid strand core from breaking through the initially thin, already solidified strand shell, the liquid metal is initially poured slowly. Due to the low specific mass flow, the metal strand cannot maintain sufficiently high rolling temperatures for rolling in the individual stands of the rolling stand group. The temperatures of the rolled stock as it passes through the rolling stand group would therefore initially be insufficient for the rolling process. However, the mass flow and thus the casting speed can subsequently be increased. This causes the temperature of the metal strand to rise when it reaches the rolling stand group.

[0078] In step Y2, a check is therefore carried out to determine whether a predetermined rolling criterion has been met. For example, it can be checked whether the metal strand in the casting arch or the casting process has stabilized and / or whether the temperature and / or the specific mass flow of the metal strand are sufficient to carry out the rolling process, possibly after additional heating by means of an inductive heating arrangement arranged upstream of the rolling stand group. This check can be carried out by sensory recording, among other things, of the strand temperature, taking the specific mass flow into account. Alternatively, it is also conceivable to model the strand temperature based on operating parameters of the casting and rolling plant, in particular the casting machine. Such operating parameters can include, for example, the casting speed, a width-dependent mass flow into or out of the mold, the strand width and thickness, a cooling capacity at the casting arch, and / or the like.

[0079] Once the metal strand has reached a desired specific mass flow or, upon entering the rolling stand group, a predetermined rolling temperature, i.e., the temperature of the metal strand required or desired for rolling, in particular a temperature sufficient to achieve a desired final rolling temperature in the last rolling stand of the rolling stand group, or can be brought to this temperature by means of additional heating, a strand section is separated from the metal strand in a step Y3 by means of a first separating device. This strand section can be removed from the casting and rolling mill, for example by means of a removal system arranged in the region of the first separating device. It is conceivable for this strand section to be cut into several strand pieces by means of the first separating device and for these strand pieces to be removed.In this case, the first separating device separates strand pieces from the metal strand, essentially as soon as the head end exits the casting machine. The separation of strand pieces is then terminated when the rolling temperature is reached or attained. The strand part is therefore not present as a whole, but only as the strand pieces successively separated from the metal strand, which can considerably simplify the process.

[0080] In an optional step Y4, the metal strand is heated by means of the inductive heating arrangement to the rolling temperature or a temperature sufficient to reach the rolling temperature, provided that the casting heat alone is not sufficient for the rolling process.

[0081] FIG 5 shows an example of a shutdown Z of a casting and rolling plant.

[0082] First, in step Z1, the casting speed of a casting machine for casting a Meta II strand is reduced. This reduces the mass flow and thus the strand temperature as it passes through a rolling stand group located downstream of the casting machine. If this temperature drops below a predetermined rolling temperature required or desired for rolling the metal strand, the rolling process must be terminated.

[0083] Preferably, the strand temperature is therefore recorded or modeled by sensors in a step Z2, for example when leaving the casting machine, when entering the rolling stand group or when leaving the last rolling stand in the rolling stand group. If the strand temperature threatens to drop so far that the rolling temperature is not reached when entering the rolling stand group or the desired final rolling temperature is no longer reached, an inductive heating arrangement can be switched on in an optional step Z3. The metal strand is then expediently heated up again using the inductive heating arrangement before entering the rolling stand group. This allows the casting speed to be reduced even further without the desired minimum rolling temperature orfinal rolling temperature is not reached - even if, due to the low casting speed, additional heat is lost on the transport route between the casting machine and the rolling stand group or between the individual rolling stands of the rolling stand group.

[0084] If the heating output of the inductive heating system is no longer sufficient to maintain the rolling temperature, in particular the final rolling temperature, or if no heating system is switched on at all and the rolling temperature, in particular the final rolling temperature, is at risk of being undercut, the metal strand is separated by means of a first separating device in a further step Z4, thus interrupting the mass flow between the casting machine and the rolling stand group. The strand portion severed from the cast metal strand still emerging from the casting machine during separation can still be rolled into the desired hot strip. The remaining metal strand, or the metal strand still produced during the controlled stopping of the casting machine, is expediently removed from the casting and rolling mill in a further step Z5, for example by means of a removal system.In this case, strand pieces can be separated from the metal strand by means of the separating device and individually dropped into a collecting container of the removal system or removed by means of a conveyor device of the removal system, for example laterally.

[0085] Although the invention has been illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples, and other variations may be derived therefrom by those skilled in the art without departing from the scope of the invention.

[0086] 10 Casting and rolling plant

[0087] 12 Warm band

[0088] 14 Meta 11 strand

[0089] 14a Head end

[0090] 16 strand part

[0091] 16a Foot end

[0092] 18 strand pieces

[0093] 20 Casting machine

[0094] 21 First temperature measuring device

[0095] 22 mold

[0096] 23 Speed ​​measuring device

[0097] 24 casting arches

[0098] 30 first separating device

[0099] 32 pendulums

[0100] 34 self-aligning bearings

[0101] 36 Cutting edge 38a front cutting position 38b rear cutting position

[0102] 40 Descaling device

[0103] 50 Roll stand group 51-56 Roll stand 57 Second temperature measuring device

[0104] 60 cooling section

[0105] 70 two separating devices

[0106] 80, 82 reel

[0107] 90 scarfing device

[0108] 100 withdrawal system

[0109] 102 collection containers

[0110] 104 Lifting device 104a Roller 106 Conveyor device

[0111] 106a role

[0112] 110 inductive heating arrangement 120 third separating device

[0113] 200 procedures

[0114] 51 Giessen

[0115] 52 Lead

[0116] 53 reels

[0117] 54 Cooling down

[0118] 55 reels

[0119] 56 Separate

[0120] Y Start-up of a hot strip production / casting and rolling plant

[0121] Y1 Casting

[0122] Y2 Checking a rolling criterion

[0123] Y3 Separating the metal strand

[0124] Y4 Heating the metal strand

[0125] Z Shutdown of a hot strip production / casting and rolling plant

[0126] Z1 Reduce the casting speed

[0127] Z2 Recording the strand temperature

[0128] Z3 Heating the metal strand

[0129] Z4 Separating the metal strand

[0130] Z5 Removing the metal strand

[0131] R Transport direction

[0132] ST transport route

[0133] X maximum focal length

Claims

Claims 1. Casting and rolling plant (10) for the continuous production of hot strip (12) with - a casting machine (20) for casting a metal strand (14), - a first separating device (30) for separating the cast metal strand (14), - a first temperature measuring device (21) for measuring a strand temperature of the cast metal strand (14) at the outlet of the casting machine (20), - a speed measuring device (23) for measuring the strand speed at the outlet of the casting machine (20), - a descaling device (40) for descaling the cast metal strand (14), - a single rolling stand group (50) for rolling the cast or descaled metal strand (14) into a hot strip (12), - a modeling unit for calculating a final rolling temperature of the hot strip (12) at the exit of the rolling stand group (50) on the basis of the measured and / or a calculated average strand temperature and on the basis of the specific mass flow of the metal strand, - a cooling section (60) for cooling the rolled hot strip (12) to a coiling temperature, - a second temperature measuring device (57) for measuring a final rolling temperature of the rolled hot strip (12) at the exit of the rolling stand group (50), - at least two reels (80, 82) for reeling the cooled hot strip (12), and - a second separating device (70) arranged between the cooling section (60) and the at least two reels (80, 82) for separating the reeled hot strip (12) from the subsequent hot strip (12), a plant control for actuating the first separating device (30) for separating the cast metal strand (14), on the basis of the calculated or measured final rolling temperature of the hot strip (12).

2. Casting and rolling plant (10) according to claim 1, with a removal system (100) for removing strand pieces (18) separated from the cast metal strand (14) by means of the first separating device (30) from a transport path (S) defined between the casting machine (20) and the rolling stand group (50).

3. Casting and rolling plant (10) according to claim 2, wherein the removal system (100) is designed for removing short strand pieces (18) with a maximum length of 3 m or less, preferably 2 m or less, more preferably 1 m or less.

4. Casting and rolling plant (10) according to claim 2 or 3, wherein the first separating device (30) is designed as a pendulum shear and the removal system (100) is designed to remove short strand pieces (18) with a length corresponding to a maximum cutting width (X) of the pendulum shear when the casting machine (20) is at a standstill.

5. Casting and rolling plant (10) according to one of claims 2 to 4, wherein the removal system (100) comprises a lifting device (104) for lifting a strand part (16) separated from the cast metal strand (14) by means of the first separating device (30) in the region of a foot end (16a) facing the first separating device (30).

6. Casting and rolling plant (10) according to one of claims 2 to 5, wherein the removal system (100) has a conveyor device (106) arranged in a transport direction (R) of the metal strand (14) immediately behind the first separating device (30) for conveying out a strand piece (18) separated from the metal strand (14) by means of the first separating device (30).

7. Casting and rolling plant (10) according to one of claims 2 to 6, wherein the removal system (100) comprises a separating device (30) arranged directly below the first separating device Collecting container (102) for strand pieces (18) separated from the cast metal strand (14) by the first separating device (30) when the casting machine (20) is at a standstill.

8. Method (200) for the continuous production of hot strip (12), comprising: - casting (S1) a metal strand (14) by means of a casting machine (20), - guiding (S2) the cast metal strand (14) past a first separating device (30) and then through a descaling device (40); - rolling (S3) the cast metal strand (14) or the metal strand descaled by means of the descaling device (40) into a hot strip (12) in a single rolling stand group (50), - cooling (S4) the rolled hot strip (12) to a coiling temperature by means of a cooling section (60), - coiling (S5) the cooled hot strip (12) by means of at least two coilers (80, 82), and - separating (S6) the coiled hot strip (12) from the subsequent hot strip (12) by means of a second separating device (70) arranged between the cooling section (60) and the at least two coilers (80, 82), - wherein, on the basis of a mean strand temperature measured at the outlet of the casting machine (20) and / or a modeled mean strand temperature, a strand speed measured at the outlet of the casting machine (20) and taking into account the specific mass flow of the metal strand for the hot strip with a final rolling thickness (d), a final rolling temperature is calculated at the outlet of the rolling stand group (50), wherein the metal strand is then separated with the first separating device (30) if the calculated final rolling temperature is lower than a target final rolling temperature of the hot strip, or - the metal strand is then separated by the first separating device (30) when a final rolling temperature of the hot strip (12) measured at the exit of the rolling stand group (50) falls below a target final rolling temperature.

9. Method (200) according to claim 8, wherein during the start-up and / or shutdown (Y; Z) of the hot strip production and / or in the event of a malfunction, in particular in the area of ​​the rolling stand group (50) or the at least two coilers (80, 82), the cast Meta II strand (14) is separated (Y3, Z4) by means of the first separating device (30).

10. The method (200) according to claim 9, wherein during ramp-up or ramp-down (Y; Z) of hot strip production, the cast metal strand (14) is separated at least once as soon as a predetermined rolling criterion is met during ramp-up (Y) of hot strip production or this predetermined rolling criterion is no longer met during ramp-down (Z) of hot strip production.

11. The method (200) according to claim 10, wherein the metal strand (14) is separated by means of the first separating device (30) at least once as soon as the metal strand (14) reaches a predetermined rolling temperature for the rolling stand group (50) or can be heated by means of an inductive heating arrangement (110) arranged in front of the rolling stand group (50) to a temperature suitable for reaching the predetermined rolling temperature.

12. Method (200) according to claim 10 or 11, wherein the metal strand (14) is separated at least once by means of the first separating device (30) as soon as the metal strand (14) no longer reaches a predetermined rolling temperature for the rolling stand group (50) or can no longer be heated to a temperature suitable for reaching the predetermined rolling temperature by means of an inductive heating arrangement (110) arranged in front of the rolling stand group (50).

13. Method (200) according to one of claims 8 to 12, wherein during the ramp-up or ramp-down (Y; Z) of the hot strip production, the cast metal strand (14) is heated by means of an inductive heating arrangement (110) arranged in front of the rolling stand group (50) to a temperature suitable for achieving a predetermined rolling temperature for the rolling stand group (50) (Y4; Z3), until - when starting up (Y) the hot strip production, the cast metal strand (14) already contains sufficient heat upon exiting the casting machine (20) to reach the predetermined rolling temperature even without heating (Y4) by means of the inductive heating arrangement (110), or - when shutting down (Z) the hot strip production, the heating power of the inductive heating arrangement (110) is no longer sufficient to heat the cast metal strand (14) to the temperature suitable for reaching the predetermined rolling temperature (Z3).

14. Method (200) according to one of claims 8 to 13, wherein by means of the first Separating device (30) at least one strand piece (18) from the cast metal strand (14) separated (Y3; Z4) and removed from a transport path (S) defined between the casting machine (20) and the rolling stand group (50), wherein - the operation of the casting machine (20) is briefly interrupted and the cast metal strand (14) is separated in a front and rear cutting position (38a, 38b) by means of the first cutting device (30) designed as a pendulum shear, - the strand piece (18) thus produced is removed from the transport section (S) (Z5), and - the operation of the casting machine (20) is resumed and further strand pieces are separated from the cast metal strand (14) and removed from the transport line (S).

15. Method (200) according to one of claims 8 to 14, wherein by means of the first separating device (30) at least one strand piece (18) is separated (Y3; Z4) from the cast metal strand (14) and removed from a transport path (S) defined between the casting machine (20) and the rolling stand group (50), wherein - the cast metal strand (14) is separated by means of the first separating device (30) and the separated strand part (16) is lifted in the region of a foot end (16a) facing the first separating device (30), and - by means of the first separating device (30) strand pieces (18) are separated (Y3; Z4) from the cast metal strand (14) and removed from the transport path (S) below the raised foot end (16a).

Images