Roll casting installation and method for operating same
Patent Information
- Application Number
- EP2023710005
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-08-25
- Filing Date
- 2023-03-08
- Publication Date
- 2025-02-05
- Estimated Expiration
- 2043-03-08
AI Technical Summary
Casting-rolling plants face issues with surface defects and scale rolling-in due to the use of spaced support rings in tunnel furnaces, particularly affecting surface-critical steel grades, which require high surface quality and are prone to unwanted impressions and scale formation.
A dual-process line system with a ferry for transferring slabs between lines, incorporating a scarfing device to condition the surface and bypass the tunnel furnace, allowing for surface defect removal and prevention of scale rolling-in, while maintaining productivity and energy efficiency.
The system effectively removes surface defects and prevents scale formation, enhancing surface quality and energy efficiency by allowing surface conditioning outside the primary process line, thus avoiding contact with support rings and maintaining temperature consistency.
Smart Images
Figure 1.1
Abstract
Description
[0001] Casting-rolling plant and method for its operation
[0002] The invention relates to a casting and rolling plant and a method for its operation.
[0003] Casting and rolling mills are generally known in the art. They typically comprise a casting machine for casting a molten metal into a cast strand, with the cast strand having a specific casting thickness. Downstream of the casting machine, there is the casting and rolling mill, a tunnel furnace, and a rolling mill for rolling the cast strand or slabs previously separated from the cast strand. The rolling process produces a metal strip, which is cooled after rolling and wound into a coil using a coiling device.
[0004] A typical feature of the casting-rolling plant is that the freshly cast strand or the slabs separated from it are further processed, particularly rolled, directly, i.e., by utilizing the remaining casting heat. This saves time and considerable energy costs that would otherwise be required to heat the cast strand or slabs to the required rolling temperature.
[0005] Specifically, the German utility model DE 20 2012 102 639 U1 discloses the arrangement of a scarfing machine for scarfing warm slabs, arranged downstream of a casting machine.
[0006] Another prior art discloses a casting-rolling plant with the features of the preamble of patent claim 1. Accordingly, the known tunnel furnace incorporates furnace rollers having spaced-apart support rings on which a cast strand or slab rests during its transport through the tunnel furnace. The support rings are spaced apart from one another in the width direction of the cast strand or slab, i.e., in the axial direction. While the spaced-apart support rings prevent overheating of the furnace rollers, due to their spacing, the contact surface of the cast strand or slabs on these support rings is smaller than on a continuous furnace roller in the width direction.
[0007] For cast strands or slabs that are particularly heavy and / or have a particularly high entry temperature into the tunnel kiln and therefore a particularly soft surface, the increased contact pressure exerted by these support rings leads to unwanted scale intrusion or undesirable impressions in the underside of the cast strand or slab. This is particularly undesirable for surface-critical steel grades, such as those in demand by the automotive industry. At the same time, these surface-critical steel grades must also be regularly scarfed.
[0008] The invention is based on the object of further developing a known casting and rolling plant and a known method for its operation in such a way that, in particular 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 undesired rolling-in of scale or, for example, the formation of impressions of the support rings on the undersides of the corresponding cast strands or slabs in the tunnel furnace, before a subsequent rolling process.
[0009] This object is achieved in terms of device technology by the casting and rolling plants according to patent claims 1 and 7.
[0010] The casting-rolling plant according to claim 1 represents a first variant for achieving the object. It is characterized by a second process line arranged parallel to the first process line and a first ferry that can be landed at a landing point between the first separating device and the tunnel furnace, 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-rolling plant according to the invention is characterized by a scarfing 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 cast strand in the casting direction.
[0011] With the help of the scarfing device, the above-mentioned defects can be advantageously removed from the surfaces of the slabs.
[0012] In principle, the first shuttle alone is sufficient. This applies if the scarfing device and an optional downstream rolling stand in the second process line can operate in reversing mode. A slab scarfed and / or rolled in the second process line can also be moved back to the first process line via the first shuttle.
[0013] According to a first embodiment of the invention, the casting-rolling mill comprises, in addition to the first shuttle, a second shuttle for transferring the slabs from the second process line to the first process line behind the tunnel furnace and before or into the rolling mill, preferably before the first rolling stand. This creates a bypass that can be used to bypass the tunnel furnace in the first process line. The scarfing device and, optionally, also the rolling stand in the second process line are operated unidirectionally, only in the second casting direction.
[0014] The claimed bypass advantageously allows necessary or advantageous surface conditioning by scarfing to be carried out outside the first process line, thus avoiding any adverse effects on production due to potentially slower process speeds. At the same time, the bypass arrangement prevents unfavorable temperature losses. By using only one shuttle, a particularly space-saving arrangement can be achieved, especially if the negative effects caused by the support rings of the tunnel kiln are still within the permissible tolerance range.
[0015] The casting and rolling plant according to claim 7 represents a second variant for solving the problem.It is characterized by a second process line arranged parallel to the first process line and comprising: a second casting machine for producing a second cast strand; an optional second separating device arranged downstream of the second casting machine in the casting direction for optionally dividing the second cast strand into individual second slabs; a scarfing device arranged downstream of the second separating device for scarfing the second cast strand or the second slabs separated therefrom; an optional third separating device arranged downstream of the scarfing device in the casting direction for dividing the second cast strand into the second slabs, provided this has not already been done by the second separating device; and at least one ferry for transferring the second slabs from the second process line into the first process line behind the tunnel furnace or a part thereof before or into the rolling mill, preferably before the first rolling stand.
[0016] The first variant according to claim 1 essentially reduces the second process line to the scarfing device, preferably as a bypass for the tunnel furnace in the first process line, without an upstream second casting machine. In contrast, claim 7, with the second variant, claims a fully functional second casting machine upstream of the scarfing device. The second casting machine enables the production of second cast strands or second slabs in the second process line, which are scarfed and optionally also rolled there and subsequently transferred to the first process line.
[0017] In principle, a single ferry, i.e., the first or second ferry, is sufficient; therefore, "at least one ferry..." is required. The second ferry is useful if the second casting line is operated only unidirectionally, i.e., in the second casting direction. The second slabs are then transported transversely to the first process line after scarfing and, optionally, after rolling.
[0018] The rolling stand and / or the scarfing device in the second process line can optionally also be operated in reverse. This also allows the second slab to be conveyed in the rolling stand and / or the scarfing device in the opposite direction to the second casting direction. This also allows the second slab to be transferred from the second to the first casting line using the first shuttle. Preferably, however, both the first and second shuttles are available.
[0019] The second variant also offers the same advantages as described above for the first variant.
[0020] According to an embodiment of the second variant, in addition to the first ferry, a second ferry arranged downstream of the scarfing device or optionally also the third separating device is provided for transferring the second slabs from the second process line into the first process line behind the tunnel furnace and in front of or into the rolling mill, preferably in front of the first rolling stand.
[0021] The claimed bypass in the form of the second process line with the first and second shuttles advantageously offers the possibility of transferring the first slabs, for example, if they are cast from surface-critical steel grades, past the tunnel furnace 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 rolling in of scale and the formation of undesirable marks on the surface of the slabs. This consistently prevents contact of the scarfed slabs with the support rings in the tunnel furnace. At the same time, the diverted slabs are scarfed as required using the scarfing device in the second process line before being transferred to the rolling mill.
[0022] In the first and second variants, the potential product portfolio of the casting-rolling plants according to the invention is expanded compared to a conventional casting-rolling plant. In particular, it creates the possibility of producing steel grades with critical surface properties. Surface defects resulting from the casting process can be removed or at least largely reduced in the rolling plant before hot rolling – without interrupting the direct use of the slabs. Overall, the claimed plant concept increases productivity, energy efficiency, and surface quality.
[0023] The term "direct transfer" means "coming from the casting machine" or "utilizing the casting heat." The term "direct" excludes the possibility that a slab has been cooled significantly, e.g., below 900°C, before being transferred into the bypass, e.g., because it was temporarily stored in a slab yard and then transferred from there for transfer into the bypass.
[0024] 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.
[0025] The tunnel kiln is designed to homogenize the cast strands or slabs moving through it with respect to their respective temperatures, to maintain them at their respective entry temperatures into the tunnel kiln, or to heat them to a necessary rolling temperature higher than their entry temperature into the tunnel kiln. The term "tunnel kiln" here also includes a heatable or unheated roller table, preferably encapsulated with a thermally insulating hood. The tunnel kiln or roller table has rollers, preferably with the aforementioned axially spaced support rings.
[0026] The spatial meaning of the terms "before" or "upstream" is synonymous with "upstream in the casting direction." The spatial meaning of the terms "behind" or "downstream" is synonymous with "downstream in the casting direction." The temporal meaning of the term "before" remains valid regardless. Whether the term "before" is to be understood spatially or temporally in a particular case depends on the respective context.
[0027] The first and second ferries are each used for transverse transport of slabs between the first and second process lines. The term "ferry" refers to both the ferry itself and a ferry docking point. Such a docking point must be provided in a process line for the ferry to be able to dock there.
[0028] The provision of a first surface inspection device between the first casting machine and the first ferry according to a first exemplary embodiment offers the possibility of detecting defects in the surface of the first cast strand or the first slab. This, in turn, opens up the possibility of deciding, based on the detected defects, whether a slab should be subsequently scarfed or not. The result of the surface inspection can be improved by cleaning, in particular descaling, the surface of the cast strand or the slab with the aid of a first slab cleaning device before its surface inspection.
[0029] A first control device is provided for activating the first ferry during operation of the first casting machine such that the first slabs are transferred from the first process line to the second process line with the first ferry to be scarfed there in the scarfing device if at least one of the following four criteria is met:
[0030] 1. There is a customer request for scarfing the first slabs.
[0031] 2. The first metal melt is a surface-critical steel grade.
[0032] 3. In the first casting strand or in the first slabs, surface defects were detected in the first process line before reaching the first ferry, which can be remedied or reduced in severity by scarfing.
[0033] 4. A target surface quality of the slabs can only be achieved through scarfing. If none of the four criteria mentioned is met, the first control device is designed to release the landing area in the first process line, with or without the first ferry being landed, to allow the first cast strand or the first slabs to pass into the tunnel furnace.
[0034] To achieve even better surface results, it may be useful to provide a first surface leveling device between the exit of the casting machine and the first ferry to level the surface of the first cast strand or the first slabs.
[0035] The first casting machine can, for example, be designed to cast first cast strands with a particularly long metallurgical length to achieve high throughput and / or to realize continuous operation. In the second variant for solving the above-mentioned problem, the second casting machine can, in contrast, be designed to cast different steel grades than the first casting machine. Thus, the second casting machine can be designed to produce cast strands with a shorter metallurgical length than the first cast strand, which is particularly suitable for casting steel grades that are slow to cast. If these steel grades do not require scarfing, they can enter the tunnel furnace at a high inlet temperature - accepting the aforementioned disadvantages - for this purpose; they are transferred from the second process line into the first process line upstream of the tunnel furnace using the first ferry.
[0036] The second casting machine can also be designed to cast the second cast strand with a different, in particular greater, casting thickness than the first casting thickness of the first cast strand. If such second cast strands or second slabs separated therefrom are to be scarfed and pass through the scarfing device for this purpose, it can be advantageous for the second slabs or the second cast strand to pass through another rolling stand, for example a reversing rolling stand, in the second process line upstream or downstream of the second ferry in order to be suitably reduced in thickness, for example to the first casting thickness. They can then subsequently - after a transfer from the second to the first process line - advantageously enter the rolling mill in the first process line with at least approximately the same thickness as a first cast strand or a first slab separated therefrom.
[0037] If the second cast strand has not yet been cut into second slabs before entering the scarfing device, this is mandatory downstream of the scarfing device using a third cutting device, because the second ferry cannot transfer endless cast strands, but only cut second slabs from the second process line to the first process line.
[0038] 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 for detecting defects on the surface of the second casting strand or the second slabs 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.
[0039] In the case of the second casting machine, it is advantageous if the first control device is further 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 are further processed there if none of the following four criteria is met:
[0040] 1. There is a customer request for scarfing the second slab.
[0041] 2. A target surface quality can only be achieved by scarfing the slab.
[0042] 3. The second melt is a surface-critical steel grade.
[0043] 4. Surface defects were detected in the second casting strand or in the second slabs in the second process line before reaching the first ferry, preferably after the second casting strand or the second slabs had been cleaned, in particular descaled.
[0044] The first control device should further be designed, in the event that none of the above criteria is met, to release the loading area in the second process line with or without the first ferry landed in order to pass the second cast strand or the second slab into the scarfing device.
[0045] For a further improvement of the surface of the second casting strand or the second slabs, it is advantageous to additionally provide a second surface leveling device between the outlet of the second casting machine and the scarfing 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.
[0046] Roller table sections are required to transfer cast strands or slabs from one unit to another, or to convey the cast strand or slabs through individual units within a process line or across process lines. These sections can be encapsulated or unencapsulated, as well as heated or unheated. They can also have roller table rollers without support rings.
[0047] The rolling mill may comprise a roughing stand and / or a finishing stand rolling mill, preferably with an upstream descaling device.
[0048] Finally, the rolling mill can be followed by a cooling section for cooling the rolled metal strip and by a coiling device for winding up the cooled metal strip.
[0049] According to a further embodiment, a heating device is mounted on the inlet side and / or outlet side of the scarfing device to prevent undesired cooling of the respective slabs or cast strand in the second process line. The provision of a moving device for the scarfing device offers the advantage that, if necessary, it can be moved from the second process line into the first process line and back again from the first process line if scarfing of a cast strand or slab is desired in the first process line.
[0050] The above-mentioned object of the invention is achieved in terms of process technology by the methods claimed in patent claims 20 and 23. The method claimed in claim 20 relates to the casting-rolling plant according to claim 1, and the method claimed in claim 23 relates to the casting-rolling plant according to claim 7. The advantages of these process-technology solutions essentially correspond to the advantages previously mentioned with regard to the claimed casting-rolling plants. In the operation of the casting-rolling plants according to the invention, four possible operating modes are essentially distinguished, which are described below as exemplary embodiments.
[0051] The description includes a total of 5 figures, where
[0052] Figure 1 shows an overview of the casting and rolling plant according to the invention;
[0053] Figure 2 shows a first embodiment of the method according to the invention,
[0054] Figure 3 shows a second embodiment of the method according to the invention;
[0055] Figure 4 shows a third embodiment of the method according to the invention; and
[0056] Figure 5 illustrates a fourth exemplary embodiment of the method according to the invention. The invention is described in detail below with reference to the figures mentioned in the form of exemplary embodiments. In all figures, the same technical elements are designated by the same reference numerals.
[0057] Figure 1 shows the casting-rolling plant 1000 according to the invention in a plan view, as would be suitable for both variants for achieving the inventive object. 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 process line using a first shuttle 160 and / or a second shuttle 180.
[0058] The first process line comprises a first casting machine 110, which in turn has a mold (not further described here) for casting a first molten metal into a first cast strand with a first casting thickness. Downstream of the mold is a strand guide for guiding the freshly cast first cast strand, preferably horizontally. Downstream of the first casting machine is a first separating device 140 for optionally dividing the first cast strand into individual first slabs. Downstream of the first separating device 140 is a landing area 160' for a first ferry 160, which is controlled by an associated controller 162. Downstream of the landing area 160' in the first casting direction 1.G are a tunnel furnace 170, a landing area 180' for a second ferry 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 multiple rolling stands. The second ferry 180 is controlled by an associated controller 182. Typically downstream of the rolling mill 190 are a cooling line 196, a fourth separating device 195, and a coiling device 197, shown in Figure 1 with a metal strip wound into a coil 198.
[0059] Between the first casting machine 110 and the first separating device 140, the first process line 100 can optionally also have a first slab cleaning device 120 and a first surface inspection device 130. A first surface leveling device 150 can also optionally be provided between the first separating device 140 and the first ferry 160.
[0060] 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 to form a second cast strand with a second casting thickness, and a downstream strand guide device for transferring the second cast strand, preferably into the horizontal position. A second separating device 240 is arranged downstream of the second casting machine 210 in the second casting direction 2.G. This is followed by a landing point 160' for the first ferry 160 as part of a bypass. The bypass further comprises a scarfing device 260, on the inlet side and / or outlet side of which heating devices 262 can be provided for heating the cast strand or slabs entering the scarfing device 260. The bypass can further comprise a rolling stand 270, preferably in the form of a reversing rolling stand, and a third separating device 280.The bypass ends with the berth 180' for the second ferry 180.
[0061] A second slab cleaning device 220 and a second surface inspection device 230 can optionally be provided between the second casting machine 210 and the second separating device 240. Finally, a second surface leveling device 250 can also optionally be provided in the second process line 200 between the second separating device 240 and the landing area 160' for the first ferry 160.
[0062] Not all of the units shown in Fig. 1 are required for the first and second variants of the casting-rolling plant according to the invention. In the second process line, only the scarfing device 260 and the first ferry 160 are common to both device variants—and are therefore absolutely necessary. All other possible units in the second process line, such as the second casting machine 210, the second slab cleaning device 220, the second surface inspection device 230, the second separating device 240 and the second surface leveling device, the heating devices 262, the rolling stand 270, and the third separating device 280, are each required only for certain operating modes or are generally optional.The second shuttle 180 is optional in the case where the potential surface damage caused by the support rings is acceptable enough to allow the surface to be scarfed, and minor surface marks caused by the support rings of the tunnel kiln 170 are acceptable. This is particularly the case if the scarfing device 260 is primarily intended to remove casting defects and particularly stubborn scale. For particularly surface-sensitive steel grades, the second shuttle 180 and the bypass of the tunnel kiln 170 are used.
[0063] The casting-rolling mill 1000 just described can be operated in four different operating modes. These are described in detail below with reference to Figures 2 to 5. Of these four operating modes, however, only the first and second operating modes fall within the scope of the present invention, because only these operating modes utilize the scarfing device in the second process line. The third and fourth operating modes can also be run on the claimed casting-rolling mills; however, they do not utilize the scarfing device according to the invention in the second process line. However, these two operating modes are nevertheless mentioned here as examples in order to illustrate various possibilities for operating the entire claimed casting-rolling mill according to Figure 1.
[0064] Figure 2 shows the casting-rolling plant 1000 according to the invention in the first variant for operation according to a first operating mode. It can be seen that for the first operating mode in the second process line, all units upstream of the first ferry 160 or its landing point 160' are unnecessary. Only the bypass shown is required from the second process line 200, in particular with the scarfing device 260 and the first ferry 160. The second ferry 180 is optional, as described further below. The first operating mode proceeds as follows:
[0065] In the first casting machine 110, the first cast strand with a first casting thickness is produced from a first metal melt. The first cast 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 separating device 140. Preferably, it can be previously cleaned, in particular descaled, in the first slab cleaning device 120 and examined for surface defects in the first surface inspection device 130. Also optionally, the surface of the first cast strand or the first slabs is optimized between the first separating device 140 and the first ferry 160 using the first surface leveling device.
[0066] If it is then determined with the aid of the first control device 162 that there is a customer request for scarfing the first slabs, that a target surface quality can only be achieved by scarfing the slab, that the first metal melt is a surface-critical steel grade and / or that there are surface defects in the first cast strand or in the first slabs before reaching the first ferry 160, the first slabs are moved from the first process line 100 to the second process line 200 with the aid of the first ferry, controlled by its control device 162. There, the first slabs then pass through the scarfing device 260 in the direction 2.G and are scarfed there in order to condition their surface. Optionally, the first slabs can then be further heated at the inlet and / or outlet of the scarfing device 260.After scarfing, the first operating mode provides for the first slabs to be transferred back to the first process line 100. For this purpose, the shuttle 160 can be used. This means that the scarfing device 260 is passed through in reverse. In this case, there is no need to provide a second shuttle.
[0067] However, an improved surface can be achieved with the aid of a second ferry 180. In this case, the first slab is moved in only one direction through the scarfing device 160 and then transferred back to the first process line 100 with the aid of the second ferry. Specifically, with the aid of the second ferry 180, they are placed in the first process line behind the tunnel furnace and preferably in front of the first rolling stand 190-1, for example a first roughing stand, in order to then be immediately rolled into a metal strip by this first rolling stand 190-1 and, if necessary, also further 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 device 195.
[0068] The described method according to the first operating mode with two shuttles is particularly suitable for surface-critical steel grades. By transferring the first slabs to the second process line 200 using the first shuttle 160 and from there, after scarfing, back to the first process line 100 using the second shuttle 180, the tunnel furnace 170 arranged between the two shuttles in the first process 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 furnace rollers within the tunnel furnace 170, effectively preventing the rolling in of scale and the formation of imprints on the surface of the first slabs.
[0069] Figure 3 illustrates the second operating mode for the casting-rolling plant according to the invention according to the second variant. In this operating mode, the second casting machine 210 is in operation instead of or in addition to the first casting machine 110. It produces a second cast strand, which is transported in the second casting direction 2.G in the second process line 200 and processed therein as follows. The second cast strand or second slabs separated therefrom fulfill(es) at least one of the above-mentioned criteria for scarfing and are therefore scarfed in the scarfing device 260 according to the invention. The second cast strand is divided into second slabs either upstream of the scarfing device 260 in the second separating device 250 or downstream of the scarfing device 260 in the third separating device 280.Finally, the second slabs are transferred from the second process line 200 to the first process line 100, preferably upstream of the rolling mill 190, using the second ferry 180. The subsequent procedure then proceeds analogously to the first operating mode. Optionally, the second cast strand in the second process line 200 can be cleaned, in particular descaled, using the second slab cleaning device and examined for possible surface defects using the second surface inspection device 230. Optionally, the surface of the second cast strand or the second slabs can be further conditioned using the second surface leveling device 250.
[0070] The second casting machine 210 can, in particular, be used to operate with a different, in particular shorter, metallurgical length than the first casting machine 110. The second casting machine 210 can also use a mold for casting cast strands with a greater casting thickness than the first casting machine 110. In this case, it can be advantageous to reduce the thickness of the second cast strand or the second slabs upstream or downstream of the scarfing device 260 in the second process line with the aid of the rolling stand 270, for example, also in a reversing manner, for example down to the first casting thickness with which the first cast 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 cast strand.
[0071] The advantage mentioned for the first operating mode, namely that the second cast strand or the second slabs do not have to be guided through the tunnel furnace 170 in the first process line, also applies to the second operating mode described here. In this way, the formation of undesirable rolling-in scale or the undesirable formation of indentations of the support rings on the surfaces of the second slabs can be effectively prevented.
[0072] Figure 4 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 cast strand, which, however, does not need to be scarfed in comparison to the second exemplary embodiment. This may be due to the fact that 1. there is no customer request for scarfing this cast strand, or that 2. a target surface quality can be achieved without scarfing the slab, or that 3. the cast strand was not cast from a surface-critical steel grade, and / or 4. no surface defects were detected in the second cast 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 cast strand or the second slabs had previously been cleaned, in particular descaled.In this case, the first control device 162 is programmed such that the second slabs are transported, unscented, from the second process line 200 to the first process line 100 upstream of the tunnel furnace 170 by means of the first shuttle 160. These second slabs then pass through the tunnel furnace in the first process line 100 and are then threaded via the second shuttle 180 into the rolling mill 190 to be reduced in thickness. The subsequent procedure corresponds to the procedure described for the first slabs in the first exemplary embodiment.
[0073] Figure 5 illustrates a fourth operating mode for the casting-rolling mill 1000 according to the invention. In this fourth operating mode, the entire second process line 200 is not present or not in operation. Only the first process line 100 is operated, either in batch mode and in semi-continuous mode or in continuous mode. Batch mode means that the first cast strand is divided into individual first slabs using the first separating device 140, each of these slabs having a weight that corresponds to the subsequent weight of a single coil 198. The metal strip resulting from the first slabs then does not need to be portioned using the fourth separating device 195.
[0074] In contrast, semi-continuous operation provides that the first cast strand is divided into larger slabs, so-called jumbo slabs or super slabs, with the aid of the first separating device 140, whose weight is greater than a single coil weight 198. The metal strip resulting 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 with the aid of the fourth separating device 195.
[0075] Finally, continuous operation provides for the cast first strand to pass through the first process 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 the first slabs using the first cutting device 140.
[0076] For all three variants mentioned above - batch operation, semi-continuous operation, and continuous operation - the first cast strand or the first slabs can optionally be cleaned with the help of the first slab cleaning device 120 and / or their surface can be inspected with the help of the first surface inspection device 130. Optionally, they can also be leveled with the help of the first surface leveling device 150 before they enter the tunnel furnace 170. The fourth operating mode, just like the previously described third operating mode, is preferably only suitable for first cast strands or first slabs that, due to their respective steel grade and / or their low entry temperature into the tunnel furnace, are not at risk of the aforementioned undesirable rolled-in scale or undesirable impressions forming on their respective surfaces as they pass through the tunnel furnace 170.
[0077] Finally, with regard to the illustration in Figure 1, it should be noted that in the described third and fourth operating modes, a transverse movement of the scarfing device 260 from the second process line 200 into the first process line 100, for example, into a gap in the tunnel furnace 170 or in front of or behind the tunnel furnace, can also be carried out for scarfing - in the case of the third operating mode - the second slabs or - in the case of the fourth operating mode - the first cast strand or the first slabs. List of reference symbols
[0078] 100 First process line
[0079] 110 First casting machine
[0080] 120 First slab cleaning facility
[0081] 130 First surface inspection device
[0082] 140 First separating device
[0083] 150 First surface leveling device
[0084] 160 First Ferry
[0085] 160' landing place for first ferry
[0086] 162 First control device
[0087] 170 Tunnel kiln, also roller table or roller table section
[0088] 180 Second Ferry
[0089] 180' landing place for second ferry
[0090] 182 Second control device
[0091] 190 rolling mill
[0092] 190-1 First rolling stand
[0093] 195 Fourth separator
[0094] 196 Cooling section
[0095] 197 Reeling device
[0096] 198 Coil
[0097] 200 Second process line
[0098] 210 Second casting machine
[0099] 220 Second slab cleaning facility
[0100] 230 Second surface inspection device
[0101] 240 Second separating device
[0102] 250 Second surface leveling device
[0103] 260 scarfing device
[0104] 262 Heating device
[0105] 270 Rolling stand, preferably reversing rolling stand
[0106] 280 Third separating device
[0107] 1000 Casting and rolling plant 1. G first casting direction
[0108] 2. G second casting direction
Claims
Patent claims:
1. A casting and rolling mill (1000) comprising at least one first casting machine (110) for casting a first molten metal into a first casting strand with a first casting thickness; a first cutting device (140) downstream of the first casting machine (110) in the casting direction for dividing the first casting strand into individual first slabs; a tunnel furnace (170) downstream of the first cutting device (140) with furnace rollers on which the first casting strand or the first slabs rest during their transport through the tunnel furnace (170); and a rolling mill (190) downstream of the tunnel furnace (170) with at least one first rolling stand (190-1) for rolling the first casting strand or the first slabs into a metal strip, wherein at least the first casting machine (110) together with the first cutting device (140), the tunnel furnace (170) and the rolling mill (190) forms a first process line (100);characterized by a second process line (200) arranged parallel to the first process line (100); a first ferry (160) that can be landed in the first process line (100) at a landing point (160') between the first separation device (140) and the tunnel kiln (170), with an associated first control device (162) for directly transferring the first slabs from the first process line (100) to a landing point (160') in the parallel second process line (200); a flame treatment device (260) provided in the second process line (200) in the casting direction (2.G) behind the landing point (160') for the first ferry for conditioning the surface of the first slabs separated from the first casting strand.
2. Casting and rolling mill according to claim 1 characterized in that a second ferry (180) is provided for transferring the slabs from a landing place (180') in the second process line (200) behind the flame-cutting device (260) to a landing place (180') in the first process line (100) behind the tunnel kiln (170) and in front of or in the rolling mill (190), preferably in front of the first rolling stand (190-1).
3. Casting rolling plant (1000) according to claim 1 or 2, characterized by a first surface inspection device (130) for detecting defects in the surface of the first casting strand or the first slabs between the outlet of the first casting machine (110) and the first ferry (160).
4. Casting and rolling plant according to claim 3, characterized by a first slab cleaning device (120) preferably upstream of the first surface inspection device (130), in particular in the form of a first descaling device.
5. Casting and rolling plant (1000) according to one of the preceding claims, characterized by the first control device (162) for activating the first ferry (160) during operation of the first casting machine (110) such that the first slabs from the first process line (100) are transferred with the first ferry (160) to the second process line (200) in order to be flame-treated there in the flame-treating device (260) if at least one of the following four criteria is met: - a customer request for the flame-treating of the first slabs has been received; - a target surface quality can only be achieved by flame-treating the slab,- - that the first metal melt is a surface-critical one steel quality; - surface defects were detected in the first casting strand or the first slabs in the first process line (100) before reaching the first ferry (160), preferably after the first casting strand or the first slabs had been previously cleaned, in particular descaled; and characterized in that the first control device (162) is otherwise configured to enable the landing point (160') in the first process line (100) with or without the first ferry (160) having landed, for the passage of the first casting strand or the first slabs into the tunnel kiln (170). Casting and rolling plant (1000) according to one of the preceding claims, characterized by a first surface leveling device (150) for leveling the surface of the first casting strand or the first slabs between the outlet of the first casting machine (110) and the first ferry (160).A casting and rolling mill (1000) comprising at least one first casting machine (110) for casting a first molten metal into a first casting strand with a first casting thickness; a first cutting device (140) downstream of the first casting machine (110) in the casting direction for dividing the first casting strand into individual first slabs; a tunnel furnace (170) downstream of the first cutting device (140) with furnace rollers on which the first casting strand or the first slabs rest during their transport through the tunnel furnace (170); and a rolling mill (190) downstream of the tunnel furnace (170) with at least one first rolling stand (190-1) for rolling the first casting strand or the first slabs into a metal strip, wherein at least the first casting machine (110) together with the first cutting device (140), the tunnel furnace (170) and the rolling mill (190). a first process line (100) is formed; characterized by a second process line (200) arranged parallel to the first process line (100) comprising: a second casting machine (210) for producing a second casting strand; an optional second separating device (240) downstream of the second casting machine (210) in the casting direction (2.G) for optionally dividing the second casting strand into individual second slabs; a flame-treating device (260) downstream of the second separating device (240) for flame-treating the second casting strand or the second slabs separated from it; a flame-treating device (260) downstream of the flame-treating device (260) in the casting direction (2.G) a downstream optional third separating device (280) for dividing the second casting strand into the second slabs, provided this has not already been done by the second separating device; and at least one transfer unit (160, 180) for transferring the second slabs from the second process line (200) to the first process line (100) downstream of the tunnel furnace (170) or a part thereof upstream of or into the rolling mill (190), preferably upstream of the first rolling stand (190-1). Casting and rolling mill (100) according to claim 7, characterized in that the transfer unit is a second transfer unit (180) downstream of the flame-cutting device (260) or optionally also downstream of the third separating device (280).Casting and rolling plant (1000) according to claim 7 or 8, characterized in that the second casting machine (210) is designed for casting the second casting strand with a different, in particular larger, casting thickness than the first casting thickness of the first casting strand; and that in the second process line (200) between the second casting machine. and the second ferry (180) a further rolling stand (270), preferably a reversing rolling stand, is arranged for reducing the thickness of the second casting strand or the second slabs, for example to the first casting thickness.
10. Casting and rolling plant (1000) according to one of claims 7 to 9, characterized in that the ferry is a first ferry (160) that can be landed in the first process line (100) at a landing point (160') between the first separation device (140) and the tunnel kiln (170) and in the second process line at a landing point (160') between the second separation device (240) and the flame-treating device (260) with an associated first control device (162) for directly transferring the second slabs from the second process line (100) into the parallel first process line (100) in front of the tunnel kiln (170).
11. Casting and rolling plant (1000) according to claim 10, characterized by a second surface inspection device (230) arranged in the second process line (200) between the outlet of the second casting machine (210) and the first ferry (160) for detecting defects in the surface of the second casting strand or the second slabs.
12. Casting and rolling plant according to claim 11, characterized by a second slab cleaning device (220) preferably upstream of the second surface inspection device (230), in particular in the form of a second descaling device.
13. Casting and rolling plant (1000) according to one of claims 10 to 12, characterized in that the first control device (162) is designed, during operation of the second casting machine (210), the landing place (160') in the second process line (200) with or without the first ferry landed (160) to enable the passage of the second casting strand or the second slabs into the flame-cutting device (260), if at least one of the following criteria is met: - a customer request to flame the second slabs has been received; - a target surface quality can only be achieved by flame-treating the slab.- - the second metal melt is a surface-critical steel grade; - surface defects were detected in the second casting strand or in the second slabs 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; and that 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 with the first ferry (160) from the second to the first process line (200, 100) in front of the tunnel kiln (170) in order to pass through it and subsequently be rolled.A casting and rolling mill (1000) according to one of claims 7 to 13, characterized by a second surface leveling device (250) arranged between the outlet of the second casting machine (210) and the flame-treating device (260), preferably upstream of the loading point (160') of the first ferry (160) in the second process line, for leveling the surface of the second casting strand or the second slabs. A casting and rolling mill (1000) according to one of the preceding claims, characterized in that the rolling mill (190) comprises a roughing mill and / or a finishing mill, preferably with a pre-assembled rolling mill. Descaling unit.
16. Casting and rolling plant (1000) according to one of the preceding claims, characterized by a cooling section (196) downstream of the rolling plant (190) in the first process line (100) for cooling the rolled metal strip and a reeling device (197) downstream of the cooling section (196) for reeling the metal strip.
17. Casting and rolling plant according to one of the preceding claims, characterized 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).
18. Casting and rolling plant (1000) according to one of the preceding claims, characterized by a traversing device for moving the flame-treating device (260) transversely from the second process line (200) into the first process line (100), for example into a gap in the tunnel furnace (170), and back again.
19. Casting rolling plant (1000) according to one of the preceding claims, characterized in that the furnace rollers in the tunnel furnace (170) have axially spaced support rings.
20. A method for operating the casting and rolling mill according to any of the preceding claims, comprising the following steps: Pouring a first molten metal into the first casting machine (110) into the first casting strand; Dividing the first casting strand in the first separation device (140) into individual first slabs; and Rolling of the first slabs in the rolling mill (190) each to one Metal strip, wherein at least the first casting machine (110) together with the first cutting device (140) and the rolling mill (190) forms a first process line (100); characterized by directly transferring the first slabs from the first process line (100) to the parallel second process line (200) before rolling; and in the second process line (200): conditioning the surface of the first slabs separated from the first casting strand by flame treatment; and optionally transferring the flame-treated first slabs from the second process line (200) back to the first process line (100) for rolling the first slabs.
21. Method according to claim 20, characterized in that the first slabs are transferred from the first process line (100) to the flame-treating device (260) in the second process line (200) only if at least one of the following four criteria is met: - a customer request for the flame-treating of the first slabs has been received; - a target surface quality can only be achieved by flame-treating the slab.- - the first metal melt is a surface-critical steel grade; - surface defects were detected in the first casting strand or in the first slabs in the first process line (100) before reaching the first ferry (160), preferably after the first casting strand or the first slabs had been previously cleaned, in particular descaled.
22. Method according to claim 20 or 21, characterized in that the surfaces of the first casting strand or the first slabs in The first process line must be cleaned, inspected with regard to its surface and / or leveled before reaching the first ferry (160).
23. Method for operating the casting and rolling mill according to any one of claims 7 to 19, comprising the following steps: Pouring a second molten metal in the second casting machine (210) into the second casting strand with a second casting thickness in the second process line (200); optionally dividing the second casting strand into individual second slabs; direct flame-treating of the second casting strand or the second slabs in the second process line (200); and Splitting the second casting strand into the second slabs after flame treatment, unless this has already been done before 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 kiln (170) and in front of the rolling mill (190) for rolling the second slabs.
24. Method according to claim 23, characterized in that the second casting strand or the second slabs remain in the second process line (200) and are flamed directly there only if at least one of the following four criteria is met: - a customer request exists for the flame treatment of the second casting strand or the second slabs; - a target surface quality can only be achieved by flame-treating the slab.- - the second metal melt is a surface-critical steel grade; - surface defects in the second casting strand or in the second slabs in the second process line (200) before reaching the first ferry (160). were detected, preferably after the second casting strand or the second slabs had been previously cleaned, in particular descaled; or that otherwise - the second casting strand is divided into the second slabs; and - the second slabs are moved into the first process line in front of the tunnel kiln before flame treatment, in order to pass through it and subsequently be rolled. Method according to claim 23 or 24, characterized in that the surfaces of the second casting strand or the second slabs are cleaned, inspected with regard to their surface, and / or leveled in the second process line (200) before reaching the loading point (160') of the first ferry (160). Method according to claims 23 to 25, characterized in that the second casting strand or the second slabs, each with the second casting thickness, which is, for example, greater than the first casting thickness of the first casting strand, are rolled and thickness-reduced in the second process line (200) before or after flame treatment, but before reaching the second ferry (180), preferably to the first casting thickness. Method according to any one of claims 20 to 26, characterized by Heating the first slabs, the second casting strand, or the second slabs in the second process line (200) before and / or after flame treatment. Method according to any one of claims 20 to 27, characterized in that, that the first or the second slabs, after being fed from the second process line (200) into the first process line (100), are rolled into the metal strip in the rolling mill (190); that the metal strip is then cooled; and that the cooled metal strip is finally wound into a coil (198). A method according to any one of claims 20 to 28, characterized in that at least one of the following range specifications applies: Casting thickness of the first and / or second casting strand: 50 - 250 mm, preferably 100 - 165 mm; Pouring speed of the first and / or second pouring strand: 1 - 8 m / min; Casting width of the first and / or second casting strand: 800 - 2,500 mm, preferably 1,000 - 2,250 mm; Intermediate strip thickness after roughing mill, but before finishing mill: 10 - 90 mm; final strip thickness of the metal strip behind the finishing mill: 0.5 - 30 mm, preferably 0.8 mm - 25.4 mm.