Temperature raising device, rolling facility, and temperature raising method

Abstract

A first IH slab heater 20 that is provided on a rolling line between a continuous casting machine 12 and a rough rolling mill 70 and a second IH slab heater 22 that is provided on a temperature raising line different from the rolling line are provided, and the first IH slab heater 20 and the second IH slab heater 22 are provided at positions deviated from each other in the transportation direction of a slab. Accordingly, the present invention provides a temperature raising device the whole of which between the continuous casting machine and the rough rolling mill can be further downsized in the width direction, a rolling facility, and a temperature raising method.

Description

TEMPERATURE RAISING DEVICE, ROLLING FACILITY, AND TEMPERATURE RAISING METHODThe present invention relates to a temperature raising device, a rolling facility, and a temperature raising method.As an example of a continuous casting rolling device and a continuous casting rolling method that can complement a temperature drop of a cast slab during abnormal operation and prevent a decrease in the actual yield of the cast slab, Patent Document 1 describes a continuous casting rolling device that includes a continuous casting machine, a cutting machine that is positioned on the exit side of the continuous casting machine and cuts an internal cast slab manufactured by the continuous casting machine, a rolling mill that presses the cast slab and is provided on the downstream side in the moving direction of the internal cast slab relative to the continuous casting machine, a tunnel furnace that is provided between the cutting machine and the rolling mill and heats up the cast slab positioned on the main route of the internal cast slab transported from the continuous casting machine to the rolling mill, and a load adjusting unit that is provided adjacent to the tunnel furnace, separates the cast slab on the main route from the exit side of the tunnel furnace, and pulls the cast slab to the entry side of the tunnel furnace onto the main route.[PTL 1] JP-2021-501056-AAs a prior art for raising the temperature of a cast slab by induction heating between a continuous casting machine and a rough rolling mill, there is a technique described in, for example, Patent Document 1.In the technique described in Patent Document 1, it is described that a cast slab is pulled from the exit side of the tunnel furnace provided on the main route between the continuous casting machine and the rolling mill to an auxiliary route, the temperature of the cast slab is raised by a reheater provided on the auxiliary route, and then it is returned to the entry side of the tunnel furnace on the main route.However, it is known that the size of an induction heating device in the width direction tends to increase due to the configuration thereof. Thus, in the technique described in Patent Document 1, when induction heating devices are provided on both the main route and the auxiliary route, a space in the width direction between the continuous casting machine and the rolling mill becomes large, and thus it is disadvantageously difficult to downsize.The present invention provides a temperature raising device the whole of which between a continuous casting machine and a rough rolling mill can be further downsized in the width direction, a rolling facility, and a temperature raising method.Means for Solving the ProblemThe present invention includes a plurality of means for solving the above problem, and as an example, provided is a temperature raising device that raises a temperature of a steel cast piece cast by a continuous casting machine, the temperature raising device includes a first induction heating device that is provided on a rolling line between the continuous casting machine and a rough rolling mill and a second induction heating device that is provided on a temperature raising line different from the rolling line, and the first induction heating device and the second induction heating device are provided at positions deviated from each other in a transportation direction of the cast piece.Advantages of the InventionAccording to the present invention, the whole temperature raising device between the continuous casting machine and the rough rolling mill can be further downsized in the width direction. Problems, configurations, and effects other than those described above will be clarified by the description of the embodiment below.FIG. 1 is a diagram for depicting an outline of a rolling facility including a temperature raising device of an embodiment.FIG. 2 is a diagram for depicting a state of an induction heating device in the temperature raising device when viewed from the side surface in the transportation direction.FIG. 3 is a diagram for depicting a state of the induction heating device in the temperature raising device when viewed from the transportation direction.FIG. 4 is a diagram for depicting an outline of a rolling facility including a temperature raising device having a different configuration of the embodiment.Modes for Carrying Out the InventionAn embodiment of a temperature raising device, a rolling facility including the same, and a temperature raising method of a cast slab (cast piece) of the present invention will be described by using FIG. 1 to FIG. 4. It should be noted that in the drawings used in the description, the same or corresponding constitutional elements will be given the same or similar characters, and repeated descriptions of these constitutional elements will be omitted in some cases.First, the overall configuration of the temperature raising device and the rolling facility including the same will be described by using FIG. 1. FIG. 1 is a diagram for depicting an outline of the rolling facility including the temperature raising device of the embodiment.A rolling facility 1 in FIG. 1 includes a continuous casting machine 12, a temperature raising device, and a rough rolling mill 70 for rolling a slab with the temperature raised by the temperature raising device, and has a configuration in which the temperature raising device for the slab is arranged between the continuous casting machine 12 and the rough rolling mill 70.The continuous casting machine 12 has a first strand 401 and a second strand 402. In the present embodiment, the same line as a rolling line is defined as the first strand 401, and the line side that is not the rolling line is defined as the second strand 402. The slab of the second strand 402 is transported to the rolling line (first strand) by a first slab transportation device 40, and then transported in the direction of the rough rolling mill 70 and the like.Although omitted for illustration reasons, a ladle is mounted on a ladle turret 10, and molten steel is poured into a tundish from the ladle. The tundish has two outlets, and the molten steel is poured into both molds of the first strand 401 and the second strand 402 from the outlets.Since the continuous casting machine 12 has two strands, cast slabs are cast in two lines and divided into slabs having a desired length by a torch cutting machine 14 located on the exit side of the continuous casting machine 12.In the case where the cast slab cannot be transported to the rough rolling mill 70 due to troubles in the rolling facility or the quality of the slab, a second slab transportation device 42 and a fourth slab transportation device 46 are used to transport the slab as a rejected material to a storage yard for rejected slab 50. In the storage yard for rejected slab 50, the rejected material is stored, and repair and inspection of the rejected material are performed if necessary.The temperature raising device of the present embodiment depicted in FIG. 1 is a device for raising the temperature of the slab cast by the continuous casting machine 12, and includes a first temperature raising device 501, a second temperature raising device 502, a first slab transportation device 40, a second slab transportation device 42, a third slab transportation device 44, a fourth slab transportation device 46, a thermometer 201 in the first temperature raising device, a thermometer 203 in the second temperature raising device, a storage yard thermometer 205, a controller 90, and the like.The first temperature raising device 501 is provided on the rolling line between the continuous casting machine 12 and the rough rolling mill 70, and has a first IH slab heater 20, a first soaking device 30, a soaking device 36, and the like. The first temperature raising device is arranged on the same line as the first strand 401 of the continuous casting machine 12.The slab transported from the continuous casting machine 12 toward the direction of the rough rolling mill 70 is heated up to a desired temperature by at least the first IH slab heater 20, is then transported to the first soaking device 30 provided on the exit side of the slab in the rolling line of the first IH slab heater 20 and using the retained heat of the slab as a heat source, and the temperature distribution in the cross section of the slab is uniformized and the rolling timing is adjusted while suppressing the heat radiation from the slab.The second temperature raising device 502 is provided between the continuous casting machine 12 and the rough rolling mill 70, and has a second IH slab heater 22, a soaking device 32, a second soaking device 34, and the like. The second temperature raising device is arranged on a temperature raising line that is the same line as the second strand 402 of the continuous casting machine 12 and different from the rolling line.The second temperature raising device 502 has the second IH slab heater 22, the soaking device 32 that is provided on the exit side of the slab in the temperature raising line of the second IH slab heater 22 and uses the retained heat of the slab as a heat source, the second soaking device 34 that is provided on the entry side of the slab in the temperature raising line of the second IH slab heater 22 and uses the retained heat of the slab as a heat source, and the like.Here, in the case where the temperature rise of the slab is insufficient in the first IH slab heater 20 of the first temperature raising device 501 and the second temperature raising device can be used, the second temperature raising device 502 is configured such that the slab is transported to the temperature raising line by the first slab transportation device 40, and heating by the second IH slab heater 22 and the heat retention in the soaking device 32, the second soaking device 34, and the like can also be performed.It should be noted that the configuration in which the first temperature raising device 501 has two heat retaining devices such as the first soaking device 30 and the soaking device 36 and the configuration in which the second temperature raising device 502 has two heat retaining devices such as the soaking device 32 and the second soaking device 34 are depicted, but both of them may include either one or three of more devices. In addition, one or more IH slab heaters may be used.FIG. 2 is a diagram for depicting a state of the induction heating device in the temperature raising device when viewed from the side surface in the transportation direction, and FIG. 3 is a diagram for depicting a state of the induction heating device in the temperature raising device when viewed from the transportation direction.The first IH slab heater 20 and the second IH slab heater 22 have one or more slab width end heaters 120 that raise the temperature of the ends of a slab S in the width direction, one or more slab whole area heaters 128 that raise the temperature of the cross section of the slab S, and one or more table rollers 116.Each of the slab width end heaters 120 in the first IH slab heater 20 and the second IH slab heater 22 has a pair of left and right core materials 124a and 124b that are formed in a substantially C shape when viewed along the transportation direction as depicted in FIG. 3 and made of iron, ferrite, or the like, and coil conductors 126 that are wound around the outer peripheries of the core materials 124a and 124b, the core materials 124a and 124b are arranged so as to face each other so that the edge portion of the slab S is positioned in the opening thereof, the coil conductors 126 are energized with a high frequency current to generate a high frequency magnetic flux inside the core materials 124a and 124b, and the edge portion of the slab S is heated up by an eddy current generated by the magnetic flux.The table roller 116 is connected to a driving motor 132 through a universal joint 130 and is configured to be rotatable forward and backward.As described above, the first IH slab heater 20 and the second IH slab heater 22 can uniformize the temperature in the cross section while uniformizing the temperature rise in the longitudinal direction of the slab by reciprocating (oscillating) the slab back and forth in the rolling direction.However, a space is required to be secured in the direction perpendicular to the transportation direction of the slab S since the slab width end heater 120 is a large facility in the width direction of the slab S, since the position of the slab width end heater is necessary to be moved in the width direction according to the width of the slab S and slab width end heater moving devices, which are not illustrated, exist on both sides, and since maintenance or the like of the slab width end heater and the slab width end heater moving devices is needed.Here, since the tundish becomes large in size when the interval between the first strand 401 and the second strand 402 becomes wide, it is required that the first strand 401 and the second strand 402 are relatively close to each other.Therefore, in the temperature raising device of the present embodiment, as depicted in FIG. 1, the first IH slab heater 20 and the second IH slab heater 22 are arranged at positions that are deviated from each other in the transportation direction, which is the casting direction, of the slab.Accordingly, the interval between the first temperature raising device 501 and the second temperature raising device 502 can be narrowed, the second strand 402 and the second temperature raising device 502 can be placed on the same line without increasing the size of the tundish, the first IH slab heater 20 and the second IH slab heater 22 can be prevented from interfering with each other, and the respective maintenance spaces can also be secured.In addition, in accordance with this, the position of the first soaking device 30 in the transportation direction in the rolling line can be arranged corresponding to the position where the second IH slab heater 22 is arranged in the adjacent temperature raising line. That is, the positions of the first soaking device 30 and the second IH slab heater 22 in the direction perpendicular to the transportation direction can be the same.Similarly, the position of the second soaking device 34 in the transportation direction in the rolling line can be arranged corresponding to the position where the first IH slab heater 20 is arranged in the adjacent rolling line. That is, the positions of the second soaking device 34 and the first IH slab heater 20 in the direction perpendicular to the transportation direction can be the same.The first soaking device 30, the soaking device 32, the second soaking device 34, and the soaking device 36 can employ a configuration in which the slab is surrounded with a panel configured using a reflector and a heat insulating material to suppress the escape of heat from the slab arranged therein and to promote to uniformize the temperature inside the slab. It is also possible to have a structure in which a heat insulating material such as a refractory is combined with an iron shell on the outside without providing a reflector. In addition, it is also effective in shortening the time of the temperature rise to arrange heating means therein and use the heating means to raise the temperature inside the heat retaining device at the start of the operation. Although gas heating may be used as the internal heating means, direct CO2emissions can be suppressed by using electric heaters.Even in the first soaking device 30, the soaking device 32, the second soaking device 34, and the soaking device 36, the table rollers 116 are provided and the temperature in the cross section can be uniformized while uniformizing the temperature rise in the longitudinal direction of the slab by reciprocating (oscillating) the slab back and forth in the rolling direction.The first slab transportation device 40 is configured to be capable of moving the slab between the downstream side of the first IH slab heater 20 of the first temperature raising device 501 in the rolling line and the downstream side of the second IH slab heater 22 of the second temperature raising device 502 in the temperature raising line.On the other hand, the second slab transportation device 42 is configured to be capable of moving the slab between the upstream side of the first IH slab heater 20 of the first temperature raising device 501 in the rolling line and the upstream side of the second IH slab heater 22 of the second temperature raising device 502 in the temperature raising line.The third slab transportation device 44 is configured to be capable of moving the slab between the storage yard for rejected slab 50 where the slab is stored and the exit side of the slab in the temperature raising line of the second temperature raising device 502.The fourth slab transportation device 46 is configured to be capable of moving the slab between the storage yard for rejected slab 50 and the entry side of the slab in the temperature raising line of the second temperature raising device 502. It should be noted that it is possible to have a configuration in which only one of the third slab transportation device 44 and the fourth slab transportation device 46 is provided.The thermometer 201 in the first temperature raising device is a thermometer provided in the first temperature raising device to measure the temperature of the slab. For example, it is configured to measure the surface temperature of the slab in the first IH slab heater 20.The thermometer 203 in the second temperature raising device is a thermometer provided in the second temperature raising device 502 to measure the temperature of the slab in the second temperature raising device 502. For example, it is configured to measure the surface temperature of the slab in the second IH slab heater 22.The storage yard thermometer 205 is a thermometer provided in the storage yard for rejected slab 50 to measure the surface temperature of the slab in the storage yard for rejected slab 50.The controller 90 predicts the average temperature of the slab and the temperature of the center of the slab on the basis of the measurement result of the temperature of the slab in one or more of the thermometer 201 in the first temperature raising device, the thermometer 203 in the second temperature raising device, and the storage yard thermometer 205 described above, and decides the transportation destination of the slab on the basis of the measured surface temperature and the predicted internal temperature.For example, the slab cast by the first strand 401 is heated up by the first IH slab heater 20 of the first temperature raising device 501 in the rolling line, and transported to the rough rolling mill 70. Similarly, the slab cast by the second strand 402 is heated up by the second IH slab heater 22 of the second temperature raising device 502 in the temperature raising line, moved from the downstream side thereof toward the downstream side of the first temperature raising device 501 in the rolling line, and transported to the rough rolling mill 70.As a different route, the slab cast by the first strand 401 is heated up by the first temperature raising device 501 and transported to the rough rolling mill 70. In addition, the slab cast by the second strand 402 is transported to the first temperature raising device 501 by the second slab transportation device 42, heated up by the first temperature raising device 501, and transported to the rough rolling mill 70.Thus, the controller 90 determines whether the slab transported from the second strand 402 is transported to either the first temperature raising device 501 or the second temperature raising device 502 on the basis of the temperature of the slab transported on the first strand 401 and the second strand 402 and the temperature of the slab at the timing of entering the rough rolling mill 70, and can switch the transportation direction of the slab.In addition, in the case where the transportation direction of the slab transported from the second strand 402 is switched to the rolling line or in the case where the casting in the second strand 402 is stopped, the controller 90 can transport the slab stored in the storage yard for rejected slab 50 to the temperature raising line by using the third slab transportation device 44 or the fourth slab transportation device 46.In this case, the temperature of the slab transported from the storage yard for rejected slab 50 is raised by induction heating in the temperature raising line, and the slab with the temperature raised in the temperature raising line can be moved from the downstream side of the second temperature raising device 502 in the temperature raising line toward the downstream side of the first temperature raising device 501 in the rolling line. Further, the slab transported from the storage yard for rejected slab 50 can be reciprocated in the temperature raising line to raise the temperature thereof.In addition, the controller 90 decides a transportation velocity in each device within the temperature raising device for the slab and controls the velocity.After finishing the heating in the temperature raising device, at first, since an oxidation scale is generated on the surface of the slab by high-temperature heating prior to rolling in the rolling facility 1, the scale on the surface is removed by a scale breaker 60 that removes the scale by spraying high-pressure water on the surface of the slab before rolling, reverse rolling is performed by the single rough rolling mill 70, unidirectional rolling is performed by a plurality of finishing rolling mill trains 75, strip cooling is performed by a run out table 80, and winding is performed by a down coiler 85. In the rolling facility 1, it is possible to arrange a plurality of rough rolling mills 70.FIG. 4 is a diagram for depicting an outline of a rolling facility including a temperature raising device having a different configuration of the embodiment.A rolling facility 1A depicted in FIG. 4 includes a continuous casting machine 12A having only a first strand 401, a temperature raising device, and a rough rolling mill 70 for rolling a slab with the temperature raised by the temperature raising device, and the configuration and operation thereof are substantially the same as those of the rolling facility 1 depicted in FIG. 1 except that the second strand 402 is omitted.Next, the effects of the present embodiment will be described.The temperature raising device that raises the temperature of the slab cast by the continuous casting machine 12 or 12A of the above-described embodiment includes: the first IH slab heater 20 that is provided on the rolling line between the continuous casting machine 12 or 12A and the rough rolling mill 70; and the second IH slab heater 22 that is provided on the temperature raising line different from the rolling line, and the first IH slab heater 20 and the second IH slab heater 22 are provided at positions deviated from each other in the transportation direction of the slab, so that even if the first IH slab heater 20 and the second IH slab heater 22 having large sizes in the width direction perpendicular to the transportation direction of the slab are provided on both the rolling line and the temperature raising line, the enlargement in the width direction can be suppressed and further downsizing can be achieved as compared with the conventional configuration.In addition, at least one of the first slab transportation device 40 that is configured to be capable of moving the slab between the downstream side of the first IH slab heater 20 in the rolling line and the downstream side of the second IH slab heater 22 in the temperature raising line, and the second slab transportation device 42 that is configured to be capable of moving the slab between the upstream side of the first IH slab heater 20 in the rolling line and the upstream side of the second IH slab heater 22 in the temperature raising line is further provided, so that since the interval between the rolling line and the temperature raising line can be shortened, the transportation distances of the first slab transportation device 40 and the second slab transportation device 42 can be shortened. Thus, a temperature drop of the cast slab can be reduced as compared with the conventional configuration, and further downsizing can be achieved.Further, the first IH slab heater 20 is provided on the rolling line between the first strand 401 included in the continuous casting machine 12 and the rough rolling mill 70, and the second IH slab heater 22 is provided on the temperature raising line to which the slab is transported from the second strand 402 included in the continuous casting machine 12, so that since the interval between the rolling line and the temperature raising line can be shortened, even when the second strand 402 and the temperature raising line are provided on the same line and being connected to the continuous casting machine 12 of the two strands, the tundish of the continuous casting machine 12 can be prevented from increasing in size.In addition, since the sizes of the widths of the first soaking device 30 and the second soaking device 34 are smaller than those of the first IH slab heater 20 and the second IH slab heater 22, by further providing the first soaking device 30 using the retained heat of the slab as a heat source at a position, in the rolling line, corresponding to the position where the second IH slab heater 22 is arranged in the transportation direction, and by further providing the second soaking device 34 using the retained heat of the slab as a heat source at a position, in the temperature raising line, corresponding to the position where the first IH slab heater 20 is arranged in the transportation direction, the downsizing in the transportation direction can be simultaneously achieved without increasing the width of the whole temperature raising device.Here, the slab is heated in order to reach target temperature of not only surface but also average, center of thickness, and etc. by measurement of surface temperature and estimation and control using online process model. Online process model can consider histories of route of slab, transition of temperature, etc.<Other>It should be noted that the present invention is not limited to the above embodiment and can be modified and applied in various ways. The embodiment described above has been described in detail to clearly explain the present invention, and is not necessarily limited to those having all the described configurations. In the above description, the case where the cast piece is a slab has been explained, but cases where the cast piece is a billet, bloom, and beam blank, etc. are also included in the present invention.Description of Reference Characters1, 1A: Rolling facility10: Ladle turret12, 12A: Continuous casting machine14: Torch cutting machine20: First IH slab heater (first induction heating device)22: Second IH slab heater (second induction heating device)30: First soaking device32, 36: Soaking device34: Second soaking device40: First slab transportation device (first transportation device)42: Second slab transportation device (second transportation device)44: Third slab transportation device (third transportation device)46: Fourth slab transportation device (fourth transportation device)50: Storage yard for rejected slab60: Scale breaker70: Rough rolling mill75: Finishing rolling mill train80: Run out table85: Down coiler90: Controller116: Table roller120: Slab width end heater124a, 124b: Core material126: Coil conductor128: Slab whole area heater130: Universal joint132: Driving motor201: Thermometer in first temperature raising device203: Thermometer in second temperature raising device205: Storage yard thermometer501: First temperature raising device502: Second temperature raising deviceS: Slab (cast piece)

Claims

1. A temperature raising device that raises a temperature of a steel cast piece cast by a continuous casting machine, the temperature raising device comprising: a first induction heating device that is provided on a rolling line between the continuous casting machine and a rough rolling mill; and a second induction heating device that is provided on a temperature raising line different from the rolling line, wherein the first induction heating device and the second induction heating device are provided at positions deviated from each other in a transportation direction of the cast piece.

2. The temperature raising device according to claim 1, further comprising: at least one of a first transportation device that is configured to be capable of moving the cast piece between a downstream side of the first induction heating device in the rolling line and a downstream side of the second induction heating device in the temperature raising line, and a second transportation device that is configured to be capable of moving the cast piece between an upstream side of the first induction heating device in the rolling line and an upstream side of the second induction heating device in the temperature raising line.

3. The temperature raising device according to claim 1, wherein the first induction heating device is provided on the rolling line between a first strand included in the continuous casting machine and the rough rolling mill, and the second induction heating device is provided on the temperature raising line to which the cast piece is transported from a second strand included in the continuous casting machine.

4. The temperature raising device according to claim 1, wherein a first soaking device using retained heat of the cast piece as a heat source is further provided at a position, in the rolling line, corresponding to a position where the second induction heating device is arranged in the transportation direction.

5. The temperature raising device according to claim 1, wherein a second soaking device using retained heat of the cast piece as a heat source is further provided at a position, in the temperature raising line, corresponding to a position where the first induction heating device is arranged in the transportation direction.

6. A rolling facility comprising: the continuous casting machine; the temperature raising device according to any one of claims 1 to 5; and the rough rolling mill for rolling the cast piece with a temperature raised by the temperature raising device.

7. A temperature raising method, comprising: raising a temperature of the cast piece by the temperature raising device according to any one of claims 1 to 5.

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