Casting and rolling plant and method for operating same

Abstract

The invention relates to a roll casting installation (1000) having: at least a first casting machine (110) for casting a first metal melt to form a first casting strand having a first casting thickness; and a first separating device for optionally splitting the first casting strand into individual first slabs. A tunnel kiln (170) is located downstream of the first separating device (140) and has kiln rollers which comprise mutually spaced supporting rings on which the first casting strand or the first slabs rest(s) while being transported through the tunnel kiln. The aim of the invention is to be able to cast even surface-critical grades of steel by means of a process line of this kind without risking undesired rolled-in scale or imprints of the supporting rings being impressed in the lower faces of the surface-critical first slabs when passing through the tunnel kiln. This aim is achieved in that a bypass is provided in the roll casting installation (1000) according to the invention, which bypass has an integrated flame-descaling device (260) and is intended for bypassing the tunnel kiln (170) in the first process line.

Description

[0001] The invention relates to a casting and rolling plant and a method for its operation.

[0002] Casting and rolling plants are generally known in the prior art. They typically comprise a casting machine for casting molten metal into a strand, the strand having a specific casting thickness. Downstream of the casting machine, the casting and rolling plant includes a tunnel furnace and a rolling mill for rolling the strand or slabs that have been previously separated from the strand. The rolling process produces a metal strip, which is cooled after rolling and wound into a coil using a reeling device.

[0003] A typical feature of the casting and rolling mill is that the freshly cast strand or the slabs separated from it are processed directly, i.e., using the remaining casting heat, particularly by rolling. This saves time and considerable energy costs that would otherwise be required to reheat the strand or slabs to the necessary rolling temperature.

[0004] Specifically, the German utility model DE 20 2012 102 639 U1 discloses the arrangement of a flame-treating machine for flame-treating warm slabs, arranged downstream of a casting machine.

[0005] European patent application EP 1 097 764 A2 discloses a casting rolling mill with the features of the preamble of claim 1. According to this application, the known tunnel kiln incorporates furnace rollers with spaced-apart support rings on which a casting strand or slab rests during its transport through the tunnel kiln. The support rings are spaced apart from one another in the lateral direction of the casting strand or slab, i.e., in the axial direction. While the spaced support rings prevent overheating of the furnace rollers, the contact area of ​​the casting strand or slab on these support rings is smaller than on a furnace roller that runs continuously in the lateral direction.

[0006] For slabs or strands that are particularly heavy and / or have a particularly high inlet temperature to the tunnel furnace and therefore a particularly soft surface, the aforementioned support rings lead to undesirable scale indentations or indentations on the underside of the slab or strand due to the increased contact pressure. This is particularly undesirable for surface-critical steel grades, such as those required by the automotive industry. At the same time, these surface-critical steel grades also require regular flame treatment.

[0007] The invention is based on the objective of further developing a known casting and rolling plant and a known method for its operation in such a way that, particularly for surface-critical steel grades, a possibility is created to avoid surface defects and near-surface defects, such as defects from the casting process or the aforementioned undesirable rolling in of scale or, for example, the formation of impressions of the support rings on the undersides of the corresponding casting strands or slabs in the tunnel furnace, before a subsequent rolling process.

[0008] This task is solved by the casting and rolling machine according to claim 1.

[0009] The casting and rolling plant according to a first embodiment is not the subject of the invention or is not claimed. It is characterized by a second process line arranged parallel to the first process line and a first ferry, which can be landed at a landing point between the first separation device and the tunnel kiln, with an associated first control device for directly transferring the first slabs from the first process line to a landing point in the parallel second process line. Furthermore, the casting and rolling plant according to the invention is characterized by a flame treatment device provided in the second process line downstream of the landing point of the first ferry for conditioning the surface of the first slabs separated from the first casting strand.

[0010] The flame-treating device can advantageously remove the aforementioned defects from the surfaces of the slabs.

[0011] In principle, the first ferry alone is sufficient. This applies if the flame cutting unit and an optional downstream rolling mill in the second process line can operate in reverse. A slab that has been flame cut and / or rolled in the second process line can also be moved back to the first process line via the first ferry.

[0012] According to a first embodiment of the invention, the casting and rolling mill has, in addition to the first transfer unit, a second transfer unit for transferring the slabs from the second process line to the first process line behind the tunnel kiln and in front of or into the rolling mill, preferably in front of the first rolling stand. This creates a bypass that allows the tunnel kiln in the first process line to be bypassed. The flame treatment unit and, optionally, the rolling stand in the second process line are operated unidirectionally, only in the direction of the second casting direction.

[0013] The proposed bypass advantageously allows necessary or beneficial surface conditioning by flame treatment to be carried out outside the primary process line, thus preventing any potential slowdown in production. Simultaneously, the bypass arrangement avoids undesirable temperature losses. Using only one ferry allows for a particularly space-saving arrangement, especially if any negative effects from the tunnel kiln's support rings remain within acceptable tolerances.

[0014] The casting and rolling plant according to claim 1 represents a second variant for solving the problem.It is characterized by a second process line arranged parallel to the first process line, comprising: a second casting machine for producing a second casting strand; an optional second cutting device downstream of the second casting machine in the casting direction for optionally dividing the second casting strand into individual second slabs; a flame-treating device downstream of the second cutting device for flame-treating the second casting strand or the second slabs separated from it; an optional third cutting device downstream of the flame-treating device for dividing the second casting strand into the second slabs, provided this has not already been done by the second cutting device; and at least one transfer unit for transferring the second slabs from the second process line to the first process line behind the tunnel kiln or a part thereof, in front of or into the rolling mill, preferably in front of the first rolling stand.

[0015] The first variant essentially reduces the second process line to the flame treatment unit, preferably as a bypass for the tunnel kiln in the first process line, without an upstream second casting machine. In contrast, claim 1, with its second variant, claims a fully functional second casting machine upstream of the flame treatment unit. The second casting machine enables the production of second casting strands or second slabs in the second process line, which are flame treated and optionally rolled there, and subsequently transferred to the first process line.

[0016] In principle, a single ferry, i.e., either the first or the second ferry, is sufficient; therefore, "at least one ferry..." is required. A second ferry is useful if the second casting line operates only unidirectionally, i.e., in the second casting direction. After flame treatment and optionally rolling, the second slabs are then transferred transversely into the first process line using the second ferry.

[0017] The rolling mill and / or the flame-treating unit in the second process line can optionally be operated in reverse. This allows for the conveying of the second slabs in the rolling mill and / or flame-treating unit in the opposite direction to the second casting direction. It also optionally allows for the transfer of the second slabs from the second to the first casting line using the first ferry. However, preferably both the first and second ferries are available.

[0018] The second option also offers the same advantages as described above for the first option.

[0019] According to one embodiment of the second variant, in addition to the first ferry, a second ferry is provided downstream of the flame-cutting unit or optionally also the third separation unit for transferring the second slabs from the second process line to the first process line behind the tunnel kiln and in front of or into the rolling mill, preferably in front of the first rolling stand.

[0020] The claimed bypass, in the form of the second process line with the first and second ferries, advantageously offers the possibility of diverting first slabs, for example, those cast from surface-critical steel grades, past the tunnel furnace and into the downstream rolling mill. The slabs diverted in this way are then not guided over the aforementioned support rings on the furnace rollers of the tunnel furnace, thus preventing the incorporation of scale and the formation of undesirable impressions on the surface of the slabs. This completely avoids contact between the flame-treated slabs and the support rings in the tunnel furnace. Simultaneously, the diverted slabs are flame-treated as desired in the second process line using the claimed flame-treating device before being fed into the rolling mill.

[0021] In the second variant, the potential product portfolio of the casting and rolling mills according to the invention is expanded compared to a known casting and rolling mill. In particular, it creates the possibility of producing even surface-critical steel grades. Surface defects resulting from the casting process can be removed or at least largely reduced before hot rolling in the rolling mill – without interrupting the direct use of the slabs. Overall, the claimed plant concept increases productivity, energy efficiency, and surface quality.

[0022] The term "direct transfer" means "coming from the casting machine" or "utilizing the casting heat." The term "direct" excludes the possibility that a slab was cooled significantly, e.g., below 900°C, before being fed into the bypass, for example, because it was temporarily stored on a slab storage area and then retrieved from there for feeding into the bypass.

[0023] The term "parallel" is not limited to its strict geometric meaning, but also includes an angle of up to + / -45° between the first and second process lines.

[0024] The tunnel kiln is designed to homogenize the casting strands or slabs moving through it with respect to their respective temperatures, to maintain them at their respective inlet temperature, or to heat them to a necessary rolling temperature higher than their inlet temperature. The term "tunnel kiln" here also includes a heated or unheated roller conveyor, preferably encapsulated with a thermal insulation hood. The tunnel kiln or roller conveyor has rollers, preferably with the aforementioned axially spaced support rings.

[0025] The spatial meaning of the terms "before" or "upstream" is synonymous with "upstream in the direction of pouring." The spatial meaning of the terms "downstream" or "downstream" is synonymous with "downstream in the direction of pouring." The temporal meaning of the term "before" remains valid regardless. Whether the term "before" is to be understood spatially or temporally in a given case depends on the specific context.

[0026] The first and second ferries each serve to transport slabs across between the first and second process lines.

[0027] The term "ferry" is used both for the ferry itself and for a ferry docking point. Such a docking point must be provided in a ferry's processing line if the ferry is to be able to dock there.

[0028] Providing a first surface inspection device between the first casting machine and the first ferry, according to a first embodiment, makes it possible to detect defects in the surface of the first casting strand or the first slab. This, in turn, allows a decision to be made, based on the detected defects, as to whether or not a slab should subsequently be flame-treated. The result of the surface inspection can be improved by cleaning the surface of the casting strand or slab, in particular by descaling it, using a first slab cleaning device before the surface inspection.

[0029] A first control device is provided to activate the first ferry when the first casting machine is in operation, such that the first slabs from the first process line are transferred to the second process line by the first ferry to be flame-treated in the flame-treating device, if at least one of the following four criteria is met: 1. There is a customer request to flame-treat the first slabs. 2. The first metal melt is a steel grade with critical surface properties. 3. Surface defects were detected in the first casting strand or on the first slabs in the first process line before they reached the first ferry; these defects can be corrected or reduced by flame-treating. 4. A target surface quality specification for the slabs can only be achieved by flame-treating.

[0030] If none of the aforementioned four criteria are met, the first control device is designed to unlock the landing point in the first process line with or without the first landed ferry to allow the first casting strand or the first slabs to pass through into the tunnel kiln.

[0031] To achieve even better surface results, it may be useful to provide a first surface leveling device between the outlet of the casting machine and the first ferry to level the surface of the first casting strand or the first slabs.

[0032] The first casting machine can, for example, be designed to cast initial casting strands with a particularly long metallurgical length to achieve high throughput and / or continuous operation. In the second variant for solving the aforementioned problem, the second casting machine can, in contrast, be designed to cast different steel grades than the first. Thus, the second casting machine can be designed to produce casting strands with a shorter metallurgical length compared to the first casting strand, which is particularly suitable for casting steel grades that are slow to cast. If these steel grades do not require flame treatment, they can enter the tunnel furnace at a high inlet temperature—accepting the aforementioned disadvantages—by being transferred from the second process line to the first process line upstream of the tunnel furnace using the first transfer unit.

[0033] The second casting machine can also be configured to cast the second casting strand with a different, and in particular greater, casting thickness than the first casting strand. If such second casting strands, or second slabs separated from them, are to be flame-treated and pass through the flame-treating unit for this purpose, it can be advantageous for the second slabs or the second casting strand to pass through another rolling mill, for example, a reversing mill, in the second processing line before or after the second casting machine to be suitably reduced in thickness, for example, to the first casting thickness. They can then, after being transferred from the second to the first processing line, advantageously enter the rolling mill in the first processing line with at least approximately the same thickness as a first casting strand or a first slab separated from it.

[0034] If the second casting strand has not yet been divided into second slabs before entering the flame cutting unit, this is absolutely necessary downstream of the flame cutting unit with the help of a third cutting unit, because the second ferry cannot transfer endless casting strands, but only separated second slabs from the second process line to the first process line.

[0035] To ensure a particularly high surface quality of the second casting strand or the second slabs, a second slab cleaning device and a downstream second surface inspection device can also be provided in the second process line - analogous to the first process line - between the outlet of the second casting machine and the first ferry to detect defects on the surface of the second casting strand or the second slabs.

[0036] In the case of the second casting machine, it is advantageous if the first control device is also designed to control the first ferry in such a way that the second slabs are transferred from the second to the first process line with the first ferry and processed there further if none of the following four criteria are met: 1. The customer has requested that the second slabs be flame-treated. 2. A target surface quality can only be achieved by flame-treating the slab. 3. The second melt is a surface-critical steel grade. 4. Surface defects were detected in the second casting strand or the second slabs in the second process line before they reached the first batch, preferably after the second casting strand or the second slabs had been cleaned, in particular descaled.

[0037] The first control unit should still be equipped, in the event that none of the aforementioned criteria are met, to unlock the loading point in the second process line with or without the first ferry having landed, for the passage of the second casting strand or the second slab into the flame-cutting unit.

[0038] To further improve the surface of the second casting strand or the second slabs, it is advantageous to provide an additional second surface leveling device between the outlet of the second casting machine and the flame treatment device, preferably in front of the landing place of the first ferry, for leveling the surface of the second casting strand or the second slabs.

[0039] Roller conveyor sections must be provided for transferring the casting strands or slabs from one unit to another, or for passing the casting strand or slabs through individual units within a process line or across process lines. These sections can be encapsulated or unencapsulated, and heated or unheated. They can also have roller conveyor rollers without support rings.

[0040] The rolling mill can include a pre-setting and / or a finishing stand rolling mill, preferably with a descaling unit upstream of each.

[0041] Finally, a cooling section for cooling the rolled metal strip can be located downstream of the rolling mill, and a reeling device for winding the cooled metal strip can be located downstream of the cooling section.

[0042] According to another embodiment, a heating device is installed on the inlet side and / or on the outlet side of the flame-treating device to prevent undesirable cooling of the respective slabs or the respective casting strand in the second process line.

[0043] Providing a transport device for the flame treatment unit offers the advantage that, if necessary, it can be moved from the second process line into the first process line and back again, should flame treatment of a casting strand or slab be desired in the first process line.

[0044] The aforementioned problem of the invention is solved process-technically by the method claimed in claim 12. The method claimed in claim 12 relates to the casting and rolling mill according to claim 1. The advantages of this process-technical solution essentially correspond to the advantages mentioned above with regard to the claimed casting and rolling mill. In the operation of the casting and rolling mill according to the invention, essentially four possible operating modes are distinguished, which are described below as exemplary embodiments.

[0045] The description includes a total of 5 figures, whereby Figure 1 shows an overview of the casting and rolling plant according to the invention; Figure 2 shows a first embodiment of the method according to the invention; Figure 3 shows a second embodiment of the method according to the invention; Figure 4 shows a third embodiment of the method according to the invention; and Figure 5 shows a fourth embodiment of the method according to the invention. illustrated.

[0046] The invention is described in detail below with reference to the figures mentioned, in the form of exemplary embodiments. In all figures, identical technical elements are designated by the same reference numerals.

[0047] Figure 1Figure 1 shows the casting and rolling plant 1000 according to the invention in a top view, as it would be suitable for solving the problem according to the invention in both variants. It consists of a first process line 100 and a second process line 200. Individual slabs can be transferred from one of the process lines to the other by means of a first ferry 160 and / or a second ferry 180.

[0048] The first process line comprises a first casting machine 110, which in turn has a mold (not specified here) for casting a first molten metal into a first casting strand with a first casting thickness. Downstream of the mold is a strand guide for guiding the freshly cast first casting strand, preferably horizontally. Downstream of the first casting machine is a first cutting device 140 for optionally dividing the first casting strand into individual first slabs. Downstream of the first cutting device 140 is a landing station 160' for a first slab 160, which is controlled by an associated control unit 162. Downstream of the landing station 160' in the first casting direction 1.G are a tunnel furnace 170, a landing station 180' for a second slab 180, and a rolling mill 190 with at least one first rolling stand 190-1.The rolling mill consists of a roughing mill and / or a finishing mill, each of which may have several rolling stands. The second ferry 180 is controlled by an associated control unit 182. Typically, downstream of the rolling mill 190 are a cooling mill 196, a fourth cutting unit 195, and a reeling unit 197. Figure 1 depicted with a metal band wound into a Coil 198.

[0049] Between the first casting machine 110 and the first separating unit 140, the first process line 100 may optionally include a first slab cleaning unit 120 and a first surface inspection unit 130. Also optionally, a first surface leveling unit 150 may be provided between the first separating unit 140 and the first ferry 160.

[0050] The second process line 200 preferably comprises a second casting machine 210, which in turn also has a mold (not shown here) for casting a second molten metal into a second casting strand with a second casting thickness and a downstream strand guiding device for transferring the second casting strand, preferably into a horizontal position. A second separating device 240 is arranged downstream of the second casting machine 210 in the second casting direction 2.G. A landing area 160' for the first slab 160 follows behind it as part of a bypass. The bypass further comprises a flame-treating device 260, at the inlet and / or outlet of which heating devices 262 may be provided for heating the casting strand(s) or slab(s) entering the flame-treating device 260. The bypass may further comprise a rolling mill 270, preferably in the form of a reversing rolling mill, and a third separating device 280.The bypass ends at landing point 180' for the second ferry 180.

[0051] A second slab cleaning unit 220 and a second surface inspection unit 230 can optionally be provided between the second casting machine 210 and the second separating unit 240. Finally, a second surface leveling unit 250 can also optionally be provided in the second process line 200 between the second separating unit 240 and the landing area 160' for the first ferry 160.

[0052] Not all of the in Fig. 1The units shown are required for both the first and second variants. In the second process line, only the flame treatment unit 260 and the first ferry 160 are common to both equipment variants – and therefore mandatory. All other possible units in the second process line, such as the second casting machine 210, the second slab cleaning unit 220, the second surface inspection unit 230, the second cutting unit 240 and the second surface leveling unit, the heating units 262, the rolling stand 270, and the third cutting unit 280, are only required for specific operating modes or are generally optional.The use of the second ferry 180 is optional if the potential surface damage caused by the support rings is acceptable enough to allow for sufficient surface treatment by flame treatment, and if minor surface marks from the support rings of the tunnel kiln 170 are acceptable. This is particularly the case if the flame treatment device 260 is primarily intended for removing casting defects and especially stubborn scale. For particularly surface-sensitive steel grades, the second ferry 180 and the bypass of the tunnel kiln 170 are used.

[0053] The casting and rolling mill 1000 described above can be operated in four different operating modes. These are described below with reference to the Figures 2 to 5described in detail. Of these four operating modes, however, only the first and second operating modes fall under the present invention, because only these operating modes utilize the flame-treating device in the second process line. The third and fourth operating modes can also be carried out on the claimed casting and rolling mills; however, they do not utilize the flame-treating device according to the invention in the second process line. These two operating modes are nevertheless mentioned here by way of example to illustrate different possibilities for operating the entire claimed casting and rolling mill according to the invention. Fig.1 to illustrate.

[0054] Figure 2Figure 1 shows the casting and rolling plant 1000, which is not according to the invention, in its first variant for operation according to a first operating mode. As stated, the first variant is not claimed. It can be seen that for the first operating mode, all units upstream of the first ferry 160 or its landing point 160' in the second process line are unnecessary. Only the bypass shown is required from the second process line 200, in particular with the flame-treating unit 260 and the first ferry 160. The second ferry 180 is optional, as described below. The first operating mode proceeds as follows: In the first casting machine 110, the first casting strand with a first casting thickness is produced from a first molten metal. The first casting strand passes through the first process line 100 in the first casting direction 1.G and is divided into individual first slabs in the first cutting unit 140.Preferably, it can be cleaned beforehand in the first slab cleaning unit 120, in particular descaled, and examined for surface defects in the first surface inspection unit 130. Optionally, the first casting strand or the first slabs are optimized in their surface between the first separation unit 140 and the first ferry 160 using the first surface leveling unit.

[0055] If, using the first control unit 162, it is determined that a customer has requested the first slabs to be flame-treated, that a target surface quality can only be achieved by flame-treating the slab, that the first molten metal is a surface-critical steel grade, and / or that surface defects are present in the first casting strand or in the first slabs before they reach the first ferry 160, the first slabs are transported from the first process line 100 to the second process line 200 using the first ferry, controlled by its control unit 162. There, the first slabs then pass through the flame-treating unit 260 in the direction of 2.G and are flame-treated to condition their surface. Optionally, the first slabs can then be further heated at the inlet and / or outlet of the flame-treating unit 260.After flame cutting, the first operating mode stipulates that the first slabs are then transferred back to the first process line 100. This can be done using either the ferry 160. This means that the flame cutting unit 260 is traversed in reverse. In this case, there is no need to provide a second ferry.

[0056] An improved surface finish can be achieved, however, with the aid of a second ferry 180. In this case, the first slab is moved through the flame-treating unit 160 in only one direction and then transferred back to the first processing line 100 with the aid of the second ferry. Specifically, with the aid of the second ferry 180, the slabs are placed in the first processing line behind the tunnel kiln and preferably in front of the first rolling stand 190-1, for example, a first roughing stand, in order to be immediately rolled into a metal strip by this first rolling stand 190-1 and, if necessary, also by other rolling stands of the rolling mill 190. If the first slabs and the resulting metal strip each contain more material than is required for a single coil 198, the metal strip can, if necessary, be portioned into a predetermined length for individual coils 198 in the fourth cutting unit 195.

[0057] The described process, according to the first operating mode with two ferries, is particularly suitable for steel grades with critical surface properties. By transferring the first slabs to the second processing line 200 using the first ferry 160, and from there, after flame treatment, back to the first processing line 100 using the second ferry 180, the tunnel kiln 170 located between the two ferries in the first processing line is bypassed. This has the advantage that these redirected first slabs do not have to be guided over the slender support rings on the kiln rollers inside the tunnel kiln 170, thus effectively preventing the incorporation of scale and the formation of indentations on the surface of the first slabs.

[0058] Figure 3Figure 2 illustrates the second operating mode for the casting and rolling plant according to the second variant of the invention. In this operating mode, the second casting machine 210 is operated instead of or in addition to the first casting machine 110. It produces a second casting strand, which is transported in the second casting direction 2.G in the second processing line 200 and processed there as follows. The second casting strand, or second slabs separated from it, fulfill(s) at least one of the aforementioned criteria for flame treatment and are therefore flame treated in the flame treatment unit 260 according to the invention. The cutting of the second casting strand into second slabs takes place either upstream of the flame treatment unit 260 in the second cutting unit 250 or downstream of the flame treatment unit 260 in the third cutting unit 280.Finally, the second slabs are transferred from the second process line 200 to the first process line 100, preferably in front of the rolling mill 190, using the second ferry 180. The subsequent procedure then proceeds analogously to the first operating mode.

[0059] Optionally, the second casting strand in the second process line 200 can be cleaned using the second slab cleaning unit, in particular descaled, and examined for possible surface defects using the second surface inspection unit 230. Optionally, the surface of the second casting strand or the second slabs can also be further conditioned using the second surface leveling unit 250.

[0060] The second casting machine 210 can, in particular, be used to operate with a different, especially shorter, metallurgical length than the first casting machine 110. The second casting machine 210 can also use a mold for casting strands with a greater casting thickness compared to the first casting machine 110. In this case, it can be advantageous to reduce the thickness of the second casting strand or slabs before or after the flame-treating unit 260 in the second process line using the rolling mill 270, for example, in a reversing process, down to the initial casting thickness with which the first casting strand is cast in the first casting machine. The second slabs can then be introduced into the rolling mill 190 with the same casting thickness as the first slabs or the first casting strand.

[0061] The second operating mode described here also offers the same advantage as the first operating mode: the second casting strand or the second slabs do not need to pass through the tunnel kiln 170 in the first process line. This effectively prevents the formation of undesirable scale indentations or indentations of the support rings on the surfaces of the second slabs.

[0062] Figure 4Figure 1 illustrates the third operating mode, in which the second casting machine 210 is again in operation instead of, or together with, the first casting machine 110. The second casting machine now produces a second casting strand, which, however, does not require flame treatment compared to the second embodiment. This can be due to the following reasons: 1. there is no customer request to flame this casting strand; 2. a target surface quality can be achieved without flame treatment of the slab; 3. the casting strand was not cast from a surface-critical steel grade; and / or 4. no surface defects were detected in the second casting strand or in the second slabs cut from it in the second process line 200 before reaching the first ferry 160, preferably after the second casting strand or the second slabs had been previously cleaned, in particular descaled.In this case, the first control unit 162 is programmed such that the second slabs are transported unflamed from the second process line 200 into the first process line 100 in front of the tunnel kiln 170 using the first ferry 160. These second slabs then pass through the tunnel kiln in the first process line 100 and are subsequently fed into the rolling mill 190 via the second ferry 180 to be thickness-reduced. The subsequent procedure corresponds to the procedure described for the first slabs in the first embodiment.

[0063] Figure 5Figure 1 illustrates a fourth operating mode for the casting and rolling mill 1000 according to the invention. In this fourth operating mode, the entire second process line 200 is either not present or not in operation. Only the first process line 100 is operated, either in batch operation and semi-continuous operation or in continuous operation. Batch operation means that the first casting strand is divided into individual first slabs by means of the first cutting device 140, each of these slabs having a weight corresponding to the later weight of a single coil 198. The resulting metal strip from the first slabs then does not need to be portioned by means of the fourth cutting device 195.

[0064] In contrast, the semi-continuous operation provides that the first casting strand is divided into larger slabs, so-called jumbo slabs or super slabs, by means of the first cutting device 140, whose weight is greater than that of a single coil 198. The resulting metal strip from these slabs at the exit of the rolling mill 190 is initially longer than a single coil 198; the metal strip is therefore portioned into corresponding individual coil lengths at the exit of the rolling mill 190 by means of the fourth cutting device 195.

[0065] The continuous operation process stipulates that the cast first strand passes through the first processing line as a whole until it reaches the exit of the rolling mill 190. Only then is the resulting metal strip portioned into suitable coil lengths using the fourth cutting device 195. This means that, in continuous operation, the first strand is not already cut into slabs using the first cutting device 140.

[0066] For all three operating modes mentioned – batch operation, semi-continuous operation, and continuous operation – the first casting strand or slabs can optionally be cleaned using the first slab cleaning unit 120 and / or their surface inspected using the first surface inspection unit 130. Optionally, they can also be leveled using the first surface leveling unit 150 before entering the tunnel kiln 170. The fourth operating mode, like the third operating mode described above, is preferably only suitable for first casting strands or slabs that, due to their respective steel grade and / or their low entry temperature into the tunnel kiln, are not at risk of developing the aforementioned undesirable scale indentations or undesirable impressions on their respective surfaces during passage through the tunnel kiln 170.

[0067] Finally, with regard to the presentation in Figure 1 It is mentioned that in the described third and fourth operating modes, a transverse process of the flame-treating device 260 from the second process line 200 into the first process line 100, for example into a gap in the tunnel kiln 170 or in front of or behind the tunnel kiln, can optionally take place for flame-treating - in the case of the third operating mode - the second slabs or - in the case of the fourth operating mode - the first casting strand or the first slabs. Reference symbol list

[0068] 100 First processing line 110 First casting machine 120 First slab cleaning unit 130 First surface inspection unit 140 First cutting unit 150 First surface leveling unit 160 First ferry 160' Landing place for first ferry 162 First control unit 170 Tunnel kiln, also roller walk or roller walk section 180 Second ferry 180' Landing place for second ferry 182 Second control unit 190 Rolling mill 190-1 First rolling stand 195 Fourth cutting unit 196 Cooling section 197 Reel unit 198 Coil 200 Second processing line 210 Second casting machine 220 Second slab cleaning unit 230 Second surface inspection unit 240 Second cutting unit 250 Second surface leveling unit 260 Flame treatment unit 262 Heating device 270 Rolling mill, preferably reversing rolling mill 280 Third separating device 1000 Casting rolling mill 1. Barley casting direction 2. Second casting direction

Claims

1. Casting and rolling plant (1000), comprising at least one first casting machine (110) for casting a first metal melt to form a first cast strip with a first cast thickness; a first separating device (140), which is downstream of the first casting machine (110) in casting direction, for dividing the first cast strip into individual first slabs; a tunnel furnace (170), which is downstream of the first separating device (140), with furnace rollers on which the first cast strip or the first slabs rests or rest during transport thereof through the tunnel furnace (170); and a rolling plant (190), which is downstream of the tunnel furnace (170), with at least one first roll stand (190-1) for rolling the first cast strip or the first slabs in each instance to form a metal strip, wherein at least the first casting machine (110) together with the first separating device (140), the tunnel furnace (170) and the rolling plant (190) forms a first process line (100); a second process line (200) arranged parallel to the first process line (100); a first ferry (160), which is dockable in the first process line (100) at a docking position (160') between the first separating device (140) and the tunnel furnace (170), with an associated first control device (162) for direct transfer of second slabs from the second process line (100) to the parallel first process line (100) in front of the tunnel furnace (170); wherein the second process line (200) comprises: at least one second ferry (180) for transfer of the second slabs from the second process line (200) to the first process line (100) behind the tunnel furnace (170) or a part thereof in front of or in the rolling plant (190), preferably in front of the first roll stand (190-1); a surface inspection device (230) for recognition of faults in the surface of the second cast strip or the second slabs; and a second slab cleaning device (220), particularly in the form of a second descaling device, preferably upstream of the surface inspection device (230); wherein the casting and rolling plant is characterised in that the second process line comprises: a second casting machine (210) for producing a second cast strip; a second separating device (240), which is downstream of the second casting machine (210) in casting direction (2.G), for dividing the second cast strip into the individual second slabs; a flame treatment device (260), which is downstream of the second separating device (240), for flame treatment of the second cast strip or the second slabs separated therefrom; and an optional third separating device (280), which is downstream of the frame treatment device (260) in casting direction (2.G), for dividing the second cast strip into the second slabs, insofar as this has not already been carried out by the second separating device; wherein the surface inspection device (230) is arranged in the second process line (200) between the outlet of the second casting machine (210) and the first ferry (160); and wherein the docking position (160') for the first ferry (160) is arranged in the second process line (200) between the second separating device (240) and the flame treatment device (260).

2. Casting and rolling plant (1000) according to claim 1, characterised in that the ferry is a second ferry (180) downstream of the flame treatment device (260) or optionally also the third separating device (280).

3. Casting and rolling plant (1000) according to claim 1 or 2, characterised in that the second casting machine (210) is configured for casting the second cast strip with a different, particularly greater, cast thickness than the first cast thickness of the first cast strip; and a further roll stand (270), preferably a reversing roll stand, for thickness reduction of the second cast strip or the second slabs, for example to the first cast thickness, is arranged in the second process line (200) between the second casting machine and the second ferry (180).

4. Casting and rolling plant (1000) according to claim 3, characterised in that the first control device (162) is configured to switch free, during operation of the second casting machine (210), the docking position (160') in the second process line (200) with or without docked first ferry (160) for the conducting through of the second cast strip or the second slabs to the flame treatment device (260) when at least one of the following criteria is fulfilled: - there is a customer wish for flame treatment of the second slabs; - a target specification for the surface quality is attainable only by flame treatment of the slab; - the second metal melt is a surface-critical steel quality; - surface faults were recognised in the second cast strip or in the second slabs in the second process line (200) before reaching the first ferry (160), preferably after the second cast strip or the second slabs were previously cleaned, in particular descaled; and the first control device (162) is further configured to otherwise control the first ferry (160) in such a way that the second slabs are transferred by the first ferry (160) from the second process line (200) to the first process line (100) in front of the tunnel furnace (170) in order to run through this and to be subsequently rolled.

5. Casting and rolling plant (1000) according to any one of claims 1 to 4, characterised by a second surface flattening device (250), which is arranged between the outlet of the second casting machine (210) and the flame treatment device (260), preferably in front of the docking position (160') of the first ferry (160) in the second process line, for flattening the surface of the second cast strip or the second slabs.

6. Casting and rolling plant (1000) according to any one of the preceding claims, characterised in that the rolling plant (190) comprises a roughing-stand rolling train and / or a finishing-stand rolling train, preferably with a respective upstream descaling device.

7. Casting and rolling plant (1000) according to any one of the preceding claims, characterised by a cooling path (196), which is downstream of the rolling plant (190) in the first process line (100), for cooling the rolled metal strip and a coiler device (197), which is downstream of the cooling path (196), for coiling the metal strip.

8. Casting and rolling plant (1000) according to any one of the preceding claims, characterised by a heating device (262) in the second process line (200) on the inlet side and / or on the outlet side of the flame treatment device (260).

9. Casting and rolling plant (1000) according to any one of the preceding claims, characterised by a moving device for transverse movement of the flame treatment device (260) from the second process line (200) into the first process line (100), for example into a gap in the tunnel furnace (17), and back again.

10. Casting and rolling plant (1000) according to any one of the preceding claims, characterised in that the furnace rollers in the tunnel furnace (170) comprise axially spaced support rings.

11. Method of operating the casting and rolling plant according to any one of claims 1 to 10, comprising the following steps: casting a second metal melt in the second casting machine (210) to form the second cast strip with a second cast thickness in the second process line (200); dividing the second cast strip into individual second slabs; direct flame treatment of the second cast strip or the second slabs in the second process line (200); and dividing the second cast strip into the second slabs after the flame treatment insofar as this was not already carried out prior to the flame treatment in the second process line (200); optional transfer of the flame-treated second slabs from the second process line (200) to the first process line, preferably behind the tunnel furnace (170) and in front of the rolling plant (190) for rolling the second slabs; characterised in that the surfaces of the second cast strip or the second slabs in the second process line (200) are cleaned, inspected with respect to the surface thereof and / or flattened before reaching the docking position (160') of the first ferry (160).

12. Method according to claim 11, characterised in that the second cast strip or the second slabs remain in the second process line (200) and are directly flame-treated thereat only when at least one of the following four criteria is fulfilled: - there is a customer wish for flame treatment of the second cast strip or the second slabs; - a target specification for the surface quality is attainable only by flame treatment of the slab; - the second metal melt is a surface-critical steel quality; - surface faults were recognised in the second cast strip or in the second slabs in the second process line (200) before reaching the first ferry (160), preferably after the second cast strip or the second slabs were previously cleaned, in particular descaled; or otherwise - the second cast strip is divided into the second slabs; and the second slabs before flame treatment in the first process line are moved in front of the tunnel furnace in order to run through this and to be subsequently rolled.

13. Method according to claim 11 or 12, characterised in that the second cast strip or the second slabs each with the second cast thickness, which for example is greater than the first cast thickness of the first cast strip, is or are rolled and reduced in thickness, preferably to the first cast thickness, in the second process line (200) before or after the flame treatment, but before reaching the second ferry (180).

14. Method according to any one of claims 11 to 13, characterised by heating the first slabs, the second cast strip or the second slabs in the second process line (200) before and / or after the flame treatment.

15. Method according to any one of claims 11 to 14, characterised in that the first or the second slabs after diversion from the second process line (200) into the first process line (100) are rolled out in the rolling plant (190) to form the metal strip; subsequently the metal strip is cooled; and the cooled metal strip is finally coiled to form a coil (198).

16. Method according to any one of claims 1 to 15, characterised in that at least one of the following range statements applies: cast thickness of the first and / or second cast strip: 50 - 250 mm, preferably 100 - 165 mm; casting speed of the first and / or second cast strip: 1 - 8 m / min; cast width of the first and / or second cast strip: 800 - 2,500 mm, preferably 1,000 - 2,250 mm; intermediate strip thickness after roughing train, but before finishing rolling train: 10 - 90 mm; final strip thickness of the metal strip behind the finishing rolling train: 0.5 - 30 mm, preferably 0.8 mm - 25.4 mm.

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