Warming device, rolling equipment provided with warming device, and method for warming casting blank

Abstract

The present invention is provided with: a first temperature raising device provided on a rolling line between a continuous casting machine (12) and a roughing mill (70); a second temperature raising device provided on a temperature raising line different from the rolling line; a first slab conveying device (40) configured so as to be capable of moving the slab (100) between the exit side of the slab (100) on the rolling line of the first heating device and the entry side of the slab (100) on the heating line of the second heating device; and a second slab conveyance device (42) configured so as to be able to move the slab (100) between the entry side of the slab (100) on the rolling line of the first temperature raising device and the exit side of the slab (100) on the temperature raising line of the second temperature raising device, the first temperature raising device having a first induction heating slab heater (20), and the second temperature raising device having a second induction heating slab heater (22). As a result, provided are: a temperature raising device capable of improving the temperature raising efficiency before a casting blank is conveyed to a roughing mill than in the prior art; a rolling facility provided with the temperature raising device; and a method for raising the temperature of the casting blank.

Description

TECHNICAL FIELD

[0001] The present application relates to a temperature raising device, a rolling apparatus provided with the temperature raising device, and a method for raising the temperature of a cast slab. BACKGROUND

[0002] In Patent Literature 1, a cast slab heating device in direct rolling is described, which is provided in a cast slab conveying line, raises the temperature of a cast slab to a rolling appropriate temperature, the cast slab conveying line conveys a cast slab of a steel cast by a continuous casting machine to a rolling mill in order to perform direct rolling of the cast slab, the cast slab heating device is provided with: a heat retaining chamber which temporarily houses a plurality of cast slabs from the continuous casting machine in the order of arrival, uses the retained heat of the cast slabs as a heat source, and is surrounded by a heat insulating material to form a chamber; a heating device which moves and heats the cast slab drawn out of the heat retaining chamber to raise the temperature of the cast slab; a temperature measuring gauge which is provided on the outlet side of the heat retaining chamber, measures the temperature of the cast slab drawn out of the heat retaining chamber in order to know whether the cast slab drawn out of the heat retaining chamber can be raised to the rolling appropriate temperature by passing once in the heating device, and a return device which returns the cast slab raised by the heating device and not reaching the rolling appropriate temperature to the heat retaining chamber in order to raise the temperature of the cast slab again by the heating device, the cast slab heating device conveys the cast slab raised to the rolling appropriate temperature by the heating device to the rolling mill. PRIOR ART DOCUMENTS PATENT LITERATURE

[0003] Patent Literature 1: Japanese Patent No. 5130139 SUMMARY PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] In order to perform direct rolling of a cast slab (billet, slab, etc.) of a steel cast by a continuous casting machine, sometimes the cast slab from the continuous casting machine is raised to a rolling appropriate temperature and then conveyed to a rolling mill.

[0005] At this time, as a prior art of a cast slab heating device in direct rolling, there is the technology described in Patent Literature 1, which is able to raise the temperature of the corresponding cast slab to the rolling appropriate temperature even in the case where a cast slab with a temperature lower than usual is conveyed from the continuous casting machine, without being discarded (removed) from the conveying line.

[0006] However, in the above technology, there is a problem that the temperature of the billet greatly decreases before the billet raised by the induction heating device and not reaching the rolling appropriate temperature is returned to the heat retaining chamber and then conveyed to the induction heating device again.

[0007] The present application provides a heating device that can improve the efficiency of heating a cast slab before it is transported to a roughing mill, a rolling apparatus having the same, and a method of heating a cast slab. Technical solution for solving the problem

[0008] The present application includes a plurality of solutions for solving the above-mentioned problems. In one example, a heating device for heating a cast slab of steel cast by a continuous casting machine, wherein the heating device comprises: a first heating device provided on a rolling line between the continuous casting machine and a roughing mill; a second heating device provided on a heating line different from the rolling line; a first conveying device configured to move the cast slab between an exit side of the cast slab on the rolling line of the first heating device and an entry side of the cast slab on the heating line of the second heating device; and a second conveying device configured to move the cast slab between an entry side of the cast slab on the rolling line of the first heating device and an exit side of the cast slab on the heating line of the second heating device, the first heating device and the second heating device having an induction heating device. Effects of the invention

[0009] With the present application, the efficiency of heating a cast slab before it is transported to a roughing mill can be improved compared to the prior art. The above-mentioned problems, structures, and effects can be clearly understood through the following description of embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 is a diagram showing an overview of a rolling apparatus of an embodiment. Figure 2 is a diagram showing the temperature of a slab just before roughing when the slab is transported without being heated. Figure 3 is a diagram showing the temperature of a slab just before roughing when the slab is transported without being heated. Figure 4 is a diagram showing the temperature of a slab just before roughing when the slab is transported without being heated. Figure 5 is a diagram showing the flow when a slab is transported to a rolling apparatus using a slab heating device of an embodiment. Figure 6 is a diagram showing the flow when a slab is transported to a rolling apparatus using a slab heating device of an embodiment. Figure 7 is a diagram showing a case where direct rolling is performed using only a first induction heating slab heater of a heating device of an embodiment. Figure 8 is a diagram showing a case where a second induction heating slab heater of a heating device of an embodiment is used in combination with the first induction heating slab heater. Figure 7A graph showing a case where the same equipment heats a slab only with the 2nd induction heating slab heater to perform direct rolling. Figure 9 A graph showing an example of a state where the heating device of the embodiment heats a waste material. Figure 10 A graph showing a relationship between a temperature change of a slab and an output of an induction heating slab heater in a case where a heat retaining device is not used in the heating device of the embodiment. Figure 11 A graph showing a relationship between a temperature change of a slab and an output of an induction heating slab heater in a case where a heat retaining device is used in the heating device of the embodiment. Figure 12 A graph showing an example when an induction heating slab heater in the heating device of the embodiment is viewed from the front. Figure 13 A graph showing a case where a difference in average temperature between a front end and a rear end of a slab. Figure 14 A graph showing a method for eliminating a temperature difference between a front end and a rear end of a slab by using the heating device of the embodiment. Figure 15 A graph showing a case where the same equipment heats a slab only with the 1st induction heating slab heater to perform direct rolling without using the 2nd induction heating slab heater by using the heating device of the embodiment. Figure 16 An example of a known equipment that heats a slab by inserting the slab into a reheating furnace. Figure 17 A graph showing an example where the heating device of the slab of the present application is provided in the equipment that heats a slab by inserting the slab into a reheating furnace. Figure 18 Another example of a graph showing when an induction heating slab heater in the heating device of the embodiment is viewed from the front. Figure 19 Still another example of a graph showing when an induction heating slab heater in the heating device of the embodiment is viewed from the front. Figure 20 A graph showing an example when an induction heating slab heater in the heating device of the embodiment is viewed from the front, which corresponds to the A-A arrow direction of Figure 12 A graph showing an example when an induction heating slab heater in the heating device of the embodiment is viewed from the front, which corresponds to the A-A arrow direction of DETAILED DESCRIPTION

[0011] Hereinafter, an embodiment of a heating device of the present application, a rolling equipment provided with the heating device, and a method for heating a slab by using the heating device will be described with reference to the drawings. In the drawings used in the present specification, the same or corresponding components are denoted by the same or similar reference numerals, and sometimes the repeated description will be omitted.

[0012] Figure 1 is a view showing an outline of the rolling apparatus of the present application. Figure 1 The rolling apparatus 1 in the above-described embodiment is a configuration in which a slab 100 heating device is arranged between a continuous casting machine 12 and a rough rolling mill 70.

[0013] The molten steel in a ladle (omitted for convenience of illustration) is moved from the ladle to an injection position for injection into the continuous casting machine 12 by a ladle turret 10. The continuous casting machine 12 is of a double strand type, and casts a casting billet in two rows, and the casting billet is divided into slabs 100 of a desired length by a flame cutter 14 located on the exit side of the continuous casting machine 12.

[0014] In this embodiment, the same line as the rolling line is set as a first strand, and the line side other than the rolling line is set as a second strand. The slab 100 of the second strand is transported toward the direction of the rough rolling mill 70 or the like after being transported to the rolling line (first strand) by the continuous casting machine exit side slab transporting device 48.

[0015] In a case where the slab 100 cast is unable to be transported to the rough rolling mill 70 due to a bad condition in the rolling apparatus or a reason on the quality of the slab 100, the slab 100 is transported to a slab storage place 50 as a scrap material using the continuous casting machine exit side slab transporting device 48. In the slab storage place 50, storage of the scrap material is performed, and trimming of the scrap material is performed as necessary.

[0016] Figure 1 The slab 100 heating device of the above-described embodiment is a device for heating the slab 100 of steel cast by the continuous casting machine 12 (refer to Figure 12 and the like), and is configured by a first induction heating slab heater 20, a first heat retaining device 30, a first slab transporting device 40, a second induction heating slab heater 22, a second heat retaining device 32, a third heat retaining device 34, a second slab transporting device 42, a third slab transporting device 44, a fourth slab transporting device 46, a first heating device inside temperature meter 201, a second heating device inside temperature meter 203, a storage place temperature meter 205, a control device 90, and the like.

[0017] After the heating by the heating device is completed, at the rolling apparatus 1, first, since the scale is generated on the surface of the slab 100 due to the high temperature heating performed before rolling, the scale on the surface is removed by a scale cleaner 60 which sprays high pressure water to the surface of the slab 100 before rolling, reversible rolling is performed by one rough rolling mill 70, unidirectional rolling is performed by a plurality of finishing rolling mill lines 75, strip cooling is performed by an output roller 80, and coiling is performed by an underground coiler 85. It is also possible to arrange a plurality of rough rolling mills 70 at the rolling apparatus 1.

[0018] The first temperature raising device is provided on a rolling line between the continuous casting machine 12 and the rough rolling machine 70, and has the first induction heating slab heater 20, the first heat retaining device 30, and the like.

[0019] The slab 100 transported from the continuous casting machine 12 toward the rolling equipment is transported to the first heat retaining device 30 provided on the out side of the slab 100 on the rolling line of the first induction heating slab heater 20 after the desired heating by the first induction heating slab heater 20, and the heat retained by the slab 100 is used as a heat source, and the slab 100 is transported to the first heat retaining device 30 while suppressing the heat dissipation from the slab 100, and the slab 100 is subjected to the uniformization of the temperature distribution in the cross section and the adjustment of the rolling timing.

[0020] It takes time to raise the temperature of the thickness center of the slab 100 whose temperature has been lowered. However, in the heating by the first induction heating slab heater 20, the surface becomes high temperature relatively quickly, and reaches the upper limit temperature allowed as the surface temperature. Then, the heating is continued while the surface temperature does not exceed the upper limit temperature, but it is necessary to reduce the supplied output (power).

[0021] For this reason, when the slab 100 is transferred to the first heat retaining device 30, the temperature of the surface of the slab 100 is lowered a little, but by raising the temperature inside the slab 100 and heating the other slab 100 by the induction heating slab heater, the center temperature of the slab 100 can be efficiently increased in the device.

[0022] That is, by repeatedly performing the heating a plurality of times by one induction heating slab heater and the soaking by the heat retaining device, compared with the case where the slab 100 is heated only by the induction heating, it is possible to shorten the time during which the slab 100 stays in the induction heating device, shorten the time interval from the start of the heating of the next slab 100 to the induction heating device, and thus it is possible to secure the time until the temperature of the thickness center is raised, and it is possible to efficiently perform the heating of a plurality of slabs 100.

[0023] The second temperature raising device is provided on a temperature raising line different from the rolling line on which the first temperature raising device is provided, and has the second induction heating slab heater 22, the second heat retaining device 32, and the third heat retaining device 34, and the like, the second heat retaining device 32 is provided on the in side of the slab 100 on the temperature raising line of the second induction heating slab heater 22, and uses the heat retained by the slab 100 as a heat source, and the third heat retaining device 34 is provided on the out side of the slab 100 on the temperature raising line of the second induction heating slab heater 22, and uses the heat retained by the slab 100 as a heat source.

[0024] The second temperature raising device is provided to heat using the second induction slab heater 22, and to heat-hold using the second heat-holding device 32, the third heat-holding device 34, and the like, in a case where the first induction slab heater 20 is insufficient to raise the temperature of the slab 100. Note that, although the second temperature raising device is shown as having both the second heat-holding device 32 and the third heat-holding device 34, it can have either one of them, or more than three.

[0025] In the above-described first heat-holding device 30, the second heat-holding device 32, and the third heat-holding device 34, the slab 100 can be caused to perform reciprocating motion (swing) to and fro in the forward direction, to achieve uniformity of the temperature in the length direction of the slab 100, and to achieve temperature-holding in the cross section. Figure 1 In the above-described first heat-holding device 30, the second heat-holding device 32, and the third heat-holding device 34, the slab 100 can be caused to perform reciprocating motion (swing) to and fro in the forward direction, to achieve uniformity of the temperature in the length direction of the slab 100, and to achieve temperature-holding in the cross section.

[0026] In the first induction slab heater 20, the second induction slab heater 22, the first heat-holding device 30, the second heat-holding device 32, and the third heat-holding device 34, a roller 130 (see FIG. 2) is provided, to enable the slab 100 to move to and fro in the forward direction. Figure 12

[0027] The first induction slab heater 20 and the second induction slab heater 22 cause the slab 100 to perform reciprocating motion (swing) to and fro in the forward direction, to achieve uniformity of the temperature in the length direction of the slab 100, and to achieve temperature-holding in the cross section. Figure 12 The first induction slab heater 20 and the second induction slab heater 22 cause the slab 100 to perform reciprocating motion (swing) to and fro in the forward direction, to achieve uniformity of the temperature in the length direction of the slab 100, and to achieve temperature-holding in the cross section.

[0028] The first heat-holding device 30, the second heat-holding device 32, and the third heat-holding device 34 can be configured to surround the slab 100 with a panel made of a reflecting plate and a heat insulating material, to suppress heat emission from the slab 100 disposed inside, and to promote temperature-holding in the slab 100. Alternatively, the heat-holding device can be configured without the reflecting plate, but with a heat insulating material like refractory and a sheet iron outside the material. Further, it is effective to shorten the temperature raising time by disposing a heating member inside the heat-holding device, and to raise the temperature in the heat-holding device in advance at the start of the operation. The heating member inside can use gas heating, but by using an electric heater, CO2 emission can be suppressed.

[0029] In the above-described first heat-holding device 30, the second heat-holding device 32, and the third heat-holding device 34, the slab 100 can be caused to perform reciprocating motion (swing) to and fro in the forward direction, to achieve uniformity of the temperature in the length direction of the slab 100, and to achieve temperature-holding in the cross section.

[0030] ​The first slab conveyance device 40 is configured to move the slab 100 between the exit side of the slab 100 on the rolling line of the first temperature increasing device and the entry side of the slab 100 on the temperature increasing line of the second temperature increasing device.

[0031] In contrast, the second slab conveyance device 42 is configured to move the slab 100 between the entry side of the slab 100 on the rolling line of the first temperature increasing device and the exit side of the slab 100 on the temperature increasing line of the second temperature increasing device.

[0032] The third slab conveyance device 44 is configured to move the slab 100 between the slab storage place 50 where the slab 100 is stored and the entry side of the slab 100 on the temperature increasing line of the second temperature increasing device. The fourth slab conveyance device 46 is configured to move the slab 100 between the slab storage place 50 and the exit side of the slab 100 on the temperature increasing line of the second temperature increasing device. In addition, either one of the third slab conveyance device 44 and the fourth slab conveyance device 46 can be provided.

[0033] The first temperature increasing device internal temperature gauge 201 is provided in the first temperature increasing device and is a temperature gauge that measures the temperature of the slab 100. For example, it is configured to measure the surface temperature of the slab 100 in the first induction heating slab heater 20.

[0034] In addition, in Figure 1 The first temperature increasing device internal temperature gauge 201 is provided in the first temperature increasing device and is a temperature gauge that measures the temperature of the slab 100. For example, it is configured to measure the surface temperature of the slab 100 in the first induction heating slab heater 20.

[0035] The second temperature increasing device internal temperature gauge 203 is provided in the second temperature increasing device and is a temperature gauge that measures the temperature of the slab 100 in the second temperature increasing device. For example, it is configured to measure the surface temperature of the slab 100 in the second induction heating slab heater 22.

[0036] Further, the second temperature-in-device thermometer 203 is also illustrated as one case, but two or more can be provided. Further, not limited to the case where the temperature of the slab 100 in the second induction heating slab heater 22 is measured, any of the cases where the temperature of the slab 100 in the second holding device 32, the third holding device 34, before entering the second induction heating slab heater 22, after coming out of the second induction heating slab heater 22, before entering the second holding device 32, the third holding device 34, after coming out of the second holding device 32, the third holding device 34, and any of the cases where two or more of the above are adopted can be provided.

[0037] The storage place thermometer 205 is provided in the slab storage place 50, and is a thermometer that measures the temperature of the slab 100 in the slab storage place 50. For example, a configuration that measures the surface temperature of the slab 100 is made.

[0038] Further, the storage place thermometer 205 is also illustrated as one case, but two or more can be provided. Further, not limited to the case where the temperature of the slab 100 in the slab storage place 50 is measured, any of the cases where the temperature of the slab 100 at the third slab conveyance device 44, the fourth slab conveyance device 46, and any of the cases where two or more of the above are adopted can be provided.

[0039] The control device 90 predicts the average temperature of the slab 100 and the temperature of the center of the slab 100 based on the measurement result of the temperature of the slab 100 obtained by any one or more of the first temperature-in-device thermometer 201, the second temperature-in-device thermometer 203, and the storage place thermometer 205, and determines the conveyance destination of the slab 100 based on the measured surface temperature and the predicted internal temperature. Details will be described later.

[0040] Figure 2 is a graph showing the temperature of the slab immediately before the rough rolling when the slab is conveyed without being warmed up, and shows the case where the casting speed Vc is 2.0 m / min, and shows the result obtained after the simulation is performed under the condition where the thickness of the slab is 225 mm and the width of the slab is 1300 mm. Figure 2 The horizontal axis shows the position in the thickness direction, and the vertical axis shows the temperature of the center in the width direction of the slab.

[0041] Further, the temperature immediately before the rough rolling is appropriately set according to the steel grade, and in this case, the case where the target temperature immediately before the rough rolling is 1150°C is described. In this case, the required average temperature increase of the slab is 105°C.

[0042] The temperature of the slab at the position where the slab is heated by the induction heating slab heater is slightly higher than the temperature of the slab at the position immediately before rough rolling, and the temperature increase by heating with the induction heating slab heater is not greatly different from Figure 2 321°C, and therefore, the temperature increase at the induction heating slab heater is set to 321°C here.

[0043] Figure 3 is a graph showing the temperature of the slab immediately before rough rolling when the slab is conveyed without being increased in temperature, and shows the case where the casting speed Vc is 1.2 m / min. Figure 3 The horizontal axis shows the position in the thickness direction, and the vertical axis shows the temperature at the center in the width direction of the slab. In Figure 3 , the temperature at the center in the thickness direction is higher than the average temperature in the thickness direction and the temperature at the surface. Figure 2 Also, the average temperature increase required for the slab is 321°C.

[0044] The temperature of the slab at the position where the slab is heated by the induction heating slab heater is slightly higher than the temperature of the slab at the position immediately before rough rolling, and the temperature increase by heating with the induction heating slab heater is not greatly different from Figure 3 321°C, and therefore, the temperature increase at the induction heating slab heater is set to 321°C here.

[0045] Figure 4 is a graph showing the temperature of the slab immediately before rough rolling when the slab is conveyed without being increased in temperature, and shows the case where the casting speed Vc is 1.2 m / min.

[0046] The temperature of the slab during conveyance is highest at the center and lowest at the surface. On the other hand, in the heating by the induction heating slab heater, heating near the surface can be performed in a relatively short time, but heating of the inside of the slab is performed by heat conduction, and therefore, time is required.

[0047] In the case where the temperature at the center in the thickness direction is low, there is a problem that the rolling load increases, and therefore, it is a target to set the average temperature to the target temperature 1150°C immediately before rough rolling (depending on the steel grade). Also, when the temperature difference is large, the thickness direction unevenness of the structure increases, and therefore, there are cases where problems such as desired toughness cannot be obtained, which becomes a cause of the thickness direction unevenness of the mechanical strength, the tensile strength, and therefore, it is also a target to make the temperature at the center in the thickness direction close to the target temperature 1150°C.

[0048] Although the surface becomes a high temperature state by the induction heating slab heater, since descaling of the slab surface is performed before rolling and the temperature of the surface decreases during conveyance, the temperature continues to decrease.

[0049] This section describes a method of heating slabs using induction heating slab heaters, focusing on the average temperature and the temperature at the center of the thickness direction, to achieve suitable rolling temperatures.

[0050] in addition, Figure 2 to Figure 4 The data are for themselves, not for others. Figure 1 The data was obtained from simulations of slabs supplied by a flow from a rolling line parallel to the rolling line (second flow). Slabs supplied from the same flow as the rolling line (first flow) tend to have a slightly higher temperature, but this is within a range that can be adjusted by heating with an induction heating slab heater.

[0051] In addition, the control device 90 determines and controls the conveying speed of the slab 100 in each device within the heating device.

[0052] Figure 2 to Figure 4 This indicates the temperature of the front end of the slab 100. The temperature of the rear end of the slab 100 is slightly higher than that of the front end. The temperature difference between the front and rear ends of the slab 100 can be adjusted by continuously heating the slab 100 as it is inserted into the induction heating slab heater. Therefore, the control device 90 can adjust the temperature in the direction of eliminating the temperature difference with the rear end, which is the last part of the slab 100 inserted into the induction heating slab heater, by continuously inserting the slab 100 into the induction heating slab heater while heating it from the front end.

[0053] Figure 5 This describes a process where a slab 100 is heated using a first induction heating slab heater 20, then kept warm using a first heat-preserving device 30, and finally conveyed to rolling mill equipment. Figure 5 In the diagram, the circled text indicates the process that corresponds to the number in parentheses below.

[0054] In this case, the control device 90 determines, based on the temperature of the slab 100 measured by the thermometer 201 inside the first heating device, whether to convey the slab 100 to the roughing mill 70 or the second heating device, and switches the conveying direction of the slab 100. Here, an example is given where the slab 100 is conveyed to the roughing mill 70 when the average temperature and center temperature of the slab 100 have reached the target.

[0055] exist Figure 5 As shown in a), for the billet cast by each stream of the dual-flow continuous casting machine 12 at a casting speed of 2.0 m / min, the billet is cut at intervals of 12 m in length of the slab 100 and conveyed toward the rolling equipment. The first slab 101 reaches the inlet side of the first induction heating slab heater 20.

[0056] The temperature of the 1st slab 101 just before rough rolling is equivalent to 1120°C at the center of thickness, 1045°C on average, and 900°C at the surface, and therefore, in order to bring the temperature in the rough rolling process to about 1150°C, as Figure 5 The heating by the 1st induction heating slab heater 20 and the heating retention by the 1st heating retention device 30 on the outgoing side are adjusted as shown in b) of the middle.

[0057] Figure 5 (1) of b) of the middle is the conveyance into the 1st induction heating slab heater 20, and by this conveyance, the front end of the slab 100 is heated by the 1st induction heating slab heater 20 in a larger amount of heat, and the rear end is heated by the 1st induction heating slab heater 20 in a smaller amount of heat. By this phenomenon, the temperature difference between the front end and the rear end is reduced. Here, the temperature difference between the average temperatures of the front end and the rear end is 50°C, and the conveyance time is set to 33 seconds to adjust to reduce this temperature difference.

[0058] Figure 5 (2) of b) of the middle indicates a state in which the slab 100 is swung (reciprocated in the rolling direction) while being heated inside the 1st induction heating slab heater 20. Here, the upper limit of the surface temperature is determined to be 1300°C. After the surface temperature reaches 1300°C, the heating of the entire slab 100 is continued while reducing the output (power) of the 1st induction heating slab heater 20 so that the surface temperature does not exceed 1300°C.

[0059] After the heating time of 121 seconds (total of 154 seconds), the temperature converted to the temperature just before rough rolling becomes equivalent to 1170°C at the center of thickness, 1230°C on average, and 1300°C at the surface.

[0060] The surface temperature decreases during the conveyance process before rough rolling, and the average temperature also decreases, but the temperature at the center of thickness is substantially constant, and therefore, the temperature at the center of thickness and the average temperature can be maintained to about 1170°C when converted to the temperature just before rough rolling.

[0061] Figure 5 (3) of c) indicates the conveyance to the 1st heating retention device 30 for 26 seconds (total of 180 seconds), and (4) indicates the swing-while-heating retention for 33 seconds (total of 213 seconds). The slab 100 of 12 m in length is produced at an interval of 6 minutes, and therefore, since it is double flow, it reaches the incoming side of the 1st induction heating slab heater 20 at an interval of 3 minutes. Therefore, at the timing of the completion of the conveyance in (3), the 2nd slab 102 reaches the incoming side of the 1st induction heating slab heater 20.

[0062] Then, as Figure 5As shown in (d), the rear end of the first slab 101 comes out of the first holding device 30. The transport of (5) takes 19 seconds (232 seconds in total), to pass through the interval LI in 232 seconds in total. The second slab 102 takes 180 seconds (3 minutes) + 154 seconds = 334 seconds to complete (1), (2), and the first slab 101 takes 213 seconds to complete (4), so there is a margin of 121 seconds (= 334 - 213). The slab 100 can be left in the first holding device 30 for an additional 121 seconds.

[0063] Figure 6 The flow is shown in which the slab 100 is heated by both the first induction heating slab heater 20 and the second induction heating slab heater 22, and then transported to the rolling apparatus. In Figure 6 , the text in the circle indicates the process corresponding to the number in the "()" below.

[0064] In this case, the control device 90 determines the number of uses and the residence time of the second induction heating slab heater 22 and the second holding device 32, the third holding device 34 of the slab 100 at the second temperature raising device based on the temperature measured by the second temperature raising device temperature gauge 203 and the rolling conditions on the rolling line, and switches the transport direction of the slab 100. Here, the control device 90 first determines to transport the slab 100 to the second temperature raising device, since the average temperature and the center temperature of the slab 100 do not reach the target.

[0065] In Figure 6 , a) indicates the period from when the first slab 101 reaches the first induction heating slab heater 20 to when it is transported out of the rolling line by the first slab transport device 40.

[0066] The slab 100 obtained by cutting the cast slab at intervals of 12 m while casting it at a casting speed of 1.2 m / min in each strand of the twin-strand continuous casting machine 12 is transported in the direction of the rolling apparatus, and the first slab 101 reaches the entry side of the first induction heating slab heater 20.

[0067] The temperature of the first slab 101 just before rough rolling corresponds to 870°C at the center of the thickness, 829°C on average, and 750°C on the surface, so the heating is adjusted below so that the temperature just before rough rolling reaches about 1150°C. In comparison Figure 5 with the case where the casting speed is 2.0 m / min, the temperature is greatly decreased. For this reason, as in (1) of Figure 5 , the temperature difference between the average temperatures of the front end and the rear end is 50°C, so the transport time is set to 33 seconds, and the first transport to the first induction heating slab heater 20 is performed in (1) to reduce the temperature difference.

[0068] Then, the slab 100 is heated while being oscillated (reciprocated in the rolling direction) inside the first induction heating slab heater 20 as in (2). Here, the upper limit of the surface temperature is set to 1300°C. After the surface temperature reaches 1300°C, the heating of the entire slab 100 is continued while lowering the output (power) of the first induction heating slab heater 20 so that the surface temperature does not exceed 1300°C.

[0069] After the heating time of 192 seconds (total of 225 seconds), the temperature converted to the temperature immediately before rough rolling becomes a temperature corresponding to 985°C at the center of the thickness, 1100°C on average, and 1300°C at the surface. However, only by the heating of the first induction heating slab heater 20, the temperature at the center of the thickness and on average does not reach 1150°C which is set as the target. For this reason, the control device 90 delivers the first slab 101 to the second temperature raising device.

[0070] In Figure 6 , b) indicates that the first slab 101 is heated by the second induction heating slab heater 22 outside the rolling line and is delivered to the rolling line by the second slab delivery device 42 until the first slab 101 is delivered to the first induction heating slab heater 20.

[0071] The delivery of (3), the heating while oscillating inside the first holding device 30 of (4), the delivery of (5), (6), and (7), and the heating while oscillating inside the second induction heating slab heater 22 of (8) are performed until the insertion to the second induction heating slab heater 22 is completed. After the heating time of 140 seconds (total of 519 seconds), the temperature converted to the temperature immediately before rough rolling becomes a temperature corresponding to 1080°C at the center of the thickness, 1165°C on average, and 1300°C at the surface. By the heating of both the first induction heating slab heater 20 and the second induction heating slab heater 22, the temperature on average exceeds 1150°C which is set as the target, but the temperature at the center of the thickness does not reach the target temperature.

[0072] In Figure 6 , c) indicates a state in which the first slab 101 is heated again by the first induction heating slab heater 20 and comes out of the first holding device.

[0073] Since the heating with both the first induction heating slab heater 20 and the second induction heating slab heater 22 is not enough, the (9) conveyance, the (10) heating while oscillating the slab inside the third holding device 34, the (11), (12) and (13) conveyances and the (14) heating while oscillating (reciprocating in the rolling direction) the slab inside the first induction heating slab heater 20 are performed for 132 seconds (total 651 seconds) until the insertion into the first induction heating slab heater 20 is completed.

[0074] The heating time is 140 seconds (total 791 seconds) and the temperature converted to the temperature just before the rough rolling becomes 1170°C at the thickness center, 1230°C on average and 1300°C on the surface. The temperature at the thickness center exceeds the target temperature 1150°C by the heating with the first induction heating slab heater 20, the second induction heating slab heater 22 and the first induction heating slab heater 20 for the second time.

[0075] The scale is removed before the rolling and the surface temperature and the average temperature are lowered during the conveyance before the rough rolling, but the temperature at the thickness center is substantially constant, so the temperature at the thickness center and the average temperature can be maintained at about 1170°C when converted to the temperature just before the rough rolling.

[0076] Further, the (15) conveyance, the (16) heating while oscillating the slab inside the first holding device 30 and the (17) conveyance are performed for 79 seconds (total 870 seconds).

[0077] The slab 100 of 12 m in length is produced at intervals of 10 minutes when the casting speed is 1.2 m / min, so it reaches the inlet side of the first induction heating slab heater 20 at intervals of 5 minutes because it is a double flow. Therefore, the timing of returning the first slab 101 to the rolling line is after the second slab 102 and the third slab 103 pass the inlet side of the first induction heating slab heater 20.

[0078] After the second time heating of the first slab 101 is completed with the first induction heating slab heater 20, the first slab 101 is conveyed toward the rough rolling mill 70. The second slab 102, the third slab 103 and the subsequent fourth slab 104, the fifth slab 105 and the like are also conveyed toward the rough rolling mill 70 while being heated three times in total with the first induction heating slab heater 20 for the first time, the second induction heating slab heater 22 and the first induction heating slab heater 20 for the second time.

[0079] Here, when it is determined that the first slab 101 is not Figure 5 the direct rolling to the rough rolling mill 70, but Figure 6In the case where the temperature is raised by additionally using the second induction heating slab heater 22, when the number of times of heating and holding by the second induction heating slab heater 22, the second holding device 32, and the third holding device 34 is determined, first, the condition for returning to the rolling line (the timing of returning and the temperature at that time) is set, and the condition for heating by the second temperature raising device (the number of times of heating and the respective heating times and the respective holding times) is determined. Then, the object slab 100 is transported in accordance with the determined condition.

[0080] At this time, when the temperature is excessively high, an adverse condition such as excessive development of surface oxidation occurs, and therefore the upper limit temperature is determined in accordance with the steel type. Therefore, the temperature of the outer surface of the slab 100 is preferably not more than the limit value. It is preferable to use the induction heating device as efficiently as possible and effectively make the most of the holding devices, thereby suppressing the amount of power consumption.

[0081] Figure 6 The description is made of raising the temperature of the slab 100 while performing the heating by the first induction heating slab heater 20, the second induction heating slab heater 22, and the first induction heating slab heater 20 for the second time, a total of three times, but there are other methods.

[0082] For example, the heating by the first induction heating slab heater 20 for the second time when the self-temperature raising line returns to the rolling line can be omitted, and the transportation to the rolling equipment can be performed.

[0083] The timing of returning the first slab 101 to the rolling line is after the passage of the third slab 103. In the case where the first slab 101 is returned to the middle between the third slab 103 and the fourth slab 104, the first induction heating slab heater 20 for the second time is used for heating the first slab 101. Figure 6 The state of (1) of the above (1) is changed to the state of the next (1) in 5 minutes (passage of the second slab 102) + 5 minutes (passage of the third slab 103) + 2.5 minutes = 12.5 minutes.

[0084] At this time, the third slab 103 preferably completes the transportation to the first holding device 30 of (3). Thereby, the heating of the first slab 101 by the first induction heating slab heater 20 for the second time can be prevented from interfering with the third slab 103. When the time required for (1), (2), and (3) of the third slab 103 is 2.5 minutes, the first slab 101 that returns once next can start the transportation to the first induction heating slab heater 20 of (1). Further, when the first slab 101 passes (1), (2), and (3) in 2.5 minutes, the next fourth slab 104 can also pass (1), (2), and (3) in 2.5 minutes.

[0085] Thus, by setting (1), (2), (3) to half the interval at which the slabs 100 arrive, even if the slabs 100 are returned from the middle of the slabs 100 outside the rolling line, the slabs 100 do not collide with each other, or the heating conditions of the slabs 100 do not become mixed.

[0086] Further, when the first heating time and the second heating time by the first induction-heating slab heater 20 are shortened, the heating time by the second induction-heating slab heater 22 can be lengthened. In the case where the heating time by the second induction-heating slab heater 22 is lengthened, the heating by the second induction-heating slab heater 22 + the holding by the second holding device 32 or the third holding device 34 can be performed in multiple times.

[0087] In order to increase the temperature of the thickness center, time is required, and by the combination of the respective heating by the first induction-heating slab heater 20, the second induction-heating slab heater 22, the induction-heating slab heater of the second time, and the holding by the respective holding devices, the high-temperature state of the slab 100 can be maintained as much as possible, and thus the temperature of the thickness center can be further increased.

[0088] In Figure 6 , from the start of the conveyance of (1) to the completion of the conveyance of (17) after returning once and being in the state of (1) again, a total of 870 seconds (14.5 minutes) elapses. In the case where the interval L1 is 56 m, for example, the average passing speed of the slab 100 during this period becomes 3.86 m / min (= 56 / 14.5). The double flow of the continuous casting machine 12 continues casting at 1.2 m / min, and thus, after the slab 100 is warmed up by the temperature-raising device, the average passing speed of the slab 100 through the temperature-raising device, 3.86 m / min, becomes in the relationship of 3.86 > 2.4 (= 1.2 x 2), and thus the slab 100 supplied from the continuous casting machine 12 can be warmed up without stopping.

[0089] Here, the case where the first slab is inserted into the first induction heating slab heater 20 after the (3) conveyance of the third slab is completed is explained, but for example, the insertion of the first slab into the first induction heating slab heater 20 can be started when the rear end of the third slab comes out of the first induction heating slab heater 20, or the insertion of the fourth slab into the first induction heating slab heater 20 can be started when the rear end of the first slab comes out of the first induction heating slab heater 20 after the first slab has been heated by the first induction heating slab heater 20 for the second time. Also, by inserting the subsequent slab into the second induction heating slab heater 22 before the (9) conveyance is completed, the time for which the slab is heated by the second induction heating slab heater 22 can be longer than explained above. The times for which the slabs are heated by the first induction heating slab heater 20 and the second induction heating slab heater 22 can be adjusted within the range where the slabs do not interfere with each other.

[0090] In addition, the flow of the slabs in the case where the first heating device and the second heating device are used alternately is not limited to the one shown in Figure 5 . Hereinafter, examples of different modes will be explained using Figure 7 and Figure 8 . Figure 7 is a view for explaining the case where direct rolling is performed using the heating device in which only the first induction heating slab heater heats the slab, Figure 8 is a view for explaining the case where direct rolling is performed using the same equipment as Figure 7 in which only the second induction heating slab heater heats the slab.

[0091] As shown in Figure 7 and Figure 8 , after the slab (the first slab) is conveyed to the first heating device of the rolling line, the next slab (the second slab) is conveyed to the second heating device of the heating line by the second slab conveyance device 42. The second slab conveyance device 42 is formed by the conveyance table 301 and the conveyance table 304. When the second slab has just reached the conveyance table 301, the conveyance table 301 is rotated. At the same time, the conveyance table 304 is rotated to convey the second slab to the conveyance table 304.

[0092] Then, the conveyance table 304 is rotated to convey the slab to the second induction heating slab heater 22. After the heating is completed, the slab is conveyed to the second holding device 32, and the second holding device is rotated while the desired holding is performed by the second holding device 32. The conveyance table 302 is also rotated, and the first slab conveyance device 40 is formed by the second holding device 32 and the conveyance table 302.

[0093] That is, during the period in which the slab is heated by the first induction heating slab heater 20 and is kept warm by the first heat keeping device 30, the next slab is heated by the second induction heating slab heater and is kept warm by the second heat keeping device 32. In this case, during the period in which the second slab is being warmed up by the second warming up device, as soon as the first warming up device is empty, the next slab is immediately transported into the first warming up device to be warmed up.

[0094] Thus, the process of supplying the slab to the descaler 60, the rough rolling mill 70 and the like of the rolling line after the slab is heated only by the first warming up device of the rolling line and the process of returning the slab to the rolling line by the first slab transporting device 40 after the slab is heated only by the second warming up device by the second slab transporting device 42 are alternately performed, whereby each slab is supplied to the rolling line 1.

[0095] Thus, the slab can be transported to the empty warming up device, so that the time during which the slab continuously transported from the continuous casting machine 12 is on standby can be reduced, and the temperature drop can be suppressed.

[0096] Since the time until the next slab is transported to the same warming up device is longer, the slab can be warmed up for a longer time by one warming up device. In the case where the Figure 7 、 Figure 8 supply pitch of the slab produced by the continuous casting machine 12 is the same, the time for heating the first slab by the first induction heating slab heater can be doubled compared to the case where Figure 5 the supply pitch is different. Thus, the slab can be sufficiently warmed up by one warming up device.

[0097] In particular, in the case where the slab is warmed up by the first warming up device, the slab does not pass through the first slab transporting device 40 and the second slab transporting device 42, so that the temperature drop of the slab can be suppressed, and the slab can be efficiently warmed up.

[0098] Figure 9 An example of the flow of heating of the waste material is shown.

[0099] When it becomes possible to roll the slab 100 stored in the slab storage place 50, after at least one heating by the second induction heating slab heater 22 and keeping warm by the second heat keeping device 32 and the third heat keeping device 34 are performed, the slab 100 can be transported to the rolling line by the second slab transporting device 42, while further heating the slab 100 by the first induction heating slab heater 20 and keeping warm by the first heat keeping device 30, the timing of rolling is adjusted.

[0100] In this case, the control device 90 determines the number of uses and the residence time of the second induction heating slab heater 22 and the second holding device 32 and the third holding device 34 of the second temperature raising device, and switches the transport direction of the slab 100, based on the temperature of the slab 100 measured by the second temperature raising device temperature gauge 203, the temperature of the slab 100 in the slab storage area 50 measured by the storage area temperature gauge 205, and the rolling conditions on the rolling line.

[0101] In detail, heating of the first slab 101 is performed in the order of "heating by the second induction heating slab heater 22 while oscillating the first slab 101, heating (first time, IH2 heating first time) by the second induction heating slab heater 22, holding (SD2 holding) by the second holding device 32, heating (second time, IH2 heating second time) by the second induction heating slab heater 22, holding (SD3 holding) by the third holding device 34, heating (third time, IH2 heating third time) by the second induction heating slab heater 22, holding (SD3 holding) by the third holding device 34, heating by the first induction heating slab heater 20, and holding by the first holding device 30" from the start of heating by the second induction heating slab heater 22 while oscillating the first slab 101. However, the present application is not limited to this. Figure 11 In detail, heating of the first slab 101 is performed in the order of "heating by the second induction heating slab heater 22 while oscillating the first slab 101, heating (first time, IH2 heating first time) by the second induction heating slab heater 22, holding (SD2 holding) by the second holding device 32, heating (second time, IH2 heating second time) by the second induction heating slab heater 22, holding (SD3 holding) by the third holding device 34, heating (third time, IH2 heating third time) by the second induction heating slab heater 22, holding (SD3 holding) by the third holding device 34, heating by the first induction heating slab heater 20, and holding by the first holding device 30" from the start of heating by the second induction heating slab heater 22 while oscillating the first slab 101. However, the present application is not limited to this.

[0102] Thus, three times of heating by the second induction heating slab heater 22 and one time of heating by the first induction heating slab heater 20 are performed, and a total of four times of heating is performed, and the desired temperature is obtained.

[0103] Here, when the slab 100 is inserted into the second temperature raising device from the slab storage area 50, it is preferable that the slab be moved into the second temperature raising device from either the second holding device 32 side or the third holding device 34 side.

[0104] In addition, when heating is further performed by the first temperature raising device after the second temperature raising device, it is preferable that the third slab transport device 44 be used to insert the slab 100 from the entry side of the second temperature raising device. In the case where heating is not performed by the first temperature raising device, it is preferable that the fourth slab transport device 46 be used to insert the slab 100 from the discharge side of the second temperature raising device. After heating is completed by the second temperature raising device, the first slab transport device 40 can also be used to transport the slab 100 to the rolling line.

[0105] Figure 10 The graph shows the relationship between the temperature of the slab 100 and the output (power) of the first induction heating slab heater 20 and the second induction heating slab heater 22 when heating is performed on the discarded slab 100 from room temperature without using a holding device.

[0106] Without a heat preservation device, the heating can be completed in the shortest possible time by continuously heating the slab using the second induction heating slab heater 22.

[0107] On the other hand, the surface of the slab 100 has an upper limit temperature, so the output of the second induction heating slab heater 22 will decrease in the middle. Figure 10 This indicates the case where the upper limit temperature of the surface is 1300°C. When the surface temperature of the slab 100 approaches the upper limit temperature, the output of the second induction heating slab heater 22 continuously decreases. Due to heat conduction into the slab 100 and heat release from the surface of the slab 100, the output of the second induction heating slab heater 22 will not be zero. In this case, let's assume that it takes time t11 to heat to the desired temperature.

[0108] Here, when the temperature drops while the slab 100 is being conveyed from outside the rolling line to the rolling line, it is heated using the first induction heating slab heater 20 of the rolling line.

[0109] Figure 11 This indicates the relationship between the temperature change of the slab 100 when a heat preservation device is used and the output (power) of the first induction heating slab heater 20 and the second induction heating slab heater 22. Figure 11 Imagine a scenario where a heat preservation device is used while the waste slab 100 is heated three times from room temperature using the second induction heating slab heater 22.

[0110] Starting with heating the first slab 101 while it is oscillating inside the second induction heating slab heater 22, the heating process proceeds as follows: "Heating of the second induction heating slab heater 22 (first heating, first IH2 heating), heat preservation by the second heat preservation device 32 (SD2 heat preservation), heating of the second induction heating slab heater 22 (second heating, second IH2 heating), heat preservation by the third heat preservation device 34 (SD3 heat preservation), heating of the second induction heating slab heater 22 (third heating, third IH2 heating), in..." Figure 11 Although not illustrated, the process includes the heat preservation of the third heat preservation device 34 (SD3 heat preservation), the heating of the first induction heating slab heater 20, and the heat preservation of the first heat preservation device 30, to heat the first slab 101.

[0111] Here, in order to efficiently heat multiple slabs 100, such as Figure 11 As shown, when the first slab 101 is kept warm using the third heat-preserving device 34, it is preferable to allow the second slab 102 to enter the second induction heating slab heater 22 for the first heating. Similarly, the third slab 103 can also be heated in the same way as the second slab 102.

[0112] existFigure 11 In the case of the first root, the surface temperature of the slab 100 reaches the upper limit temperature after the middle of the third heating, and the maximum output of the second induction heating slab heater 22 can be used for most of the time. As a result, the time taken to complete three heatings using the second induction heating slab heater 22 becomes the same as the time taken to complete three heatings using the first induction heating slab heater 20. Figure 11 t22 Figure 10 t11 Figure 11 t21

[0113] In the case of the first root, the surface temperature of the slab 100 reaches the upper limit temperature after the middle of the third heating, and the maximum output of the second induction heating slab heater 22 can be used for most of the time. As a result, the time taken to complete three heatings using the second induction heating slab heater 22 becomes the same as the time taken to complete three heatings using the first induction heating slab heater 20. Figure 11 In the case of the first root, the surface temperature of the slab 100 reaches the upper limit temperature after the middle of the third heating, and the maximum output of the second induction heating slab heater 22 can be used for most of the time. As a result, the time taken to complete three heatings using the second induction heating slab heater 22 becomes the same as the time taken to complete three heatings using the first induction heating slab heater 20.

[0114] In the case of the first root, the surface temperature of the slab 100 reaches the upper limit temperature after the middle of the third heating, and the maximum output of the second induction heating slab heater 22 can be used for most of the time. As a result, the time taken to complete three heatings using the second induction heating slab heater 22 becomes the same as the time taken to complete three heatings using the first induction heating slab heater 20. Figure 9 In the case of the first root, the surface temperature of the slab 100 reaches the upper limit temperature after the middle of the third heating, and the maximum output of the second induction heating slab heater 22 can be used for most of the time. As a result, the time taken to complete three heatings using the second induction heating slab heater 22 becomes the same as the time taken to complete three heatings using the first induction heating slab heater 20.

[0115] Next, an example of the detailed structure of the first induction heating slab heater 20 and the second induction heating slab heater 22 will be described with reference to FIG. 6. In the example shown in FIG. 6, the first induction heating slab heater 20 is exemplified, but the second induction heating slab heater 22 can also have substantially the same structure. Figure 12 Figure 12 Figure 12 A front view of the induction heating slab heater is shown.

[0116] Figure 12 ​​The illustrated first induction heating slab heater 20 has a side guide 110, and an in-plant side guide 115, a slab width end heater 120, a slab whole body heater 125, a roller table 130, a first temperature increasing device in-plant thermometer 201, and a first temperature increasing device in-side thermometer 202, which is provided on the in-side of the slab 100 on the rolling line of the first temperature increasing device, and measures the surface temperature of the slab 100.

[0117] In Figure 12 In the illustrated first induction heating slab heater 20, at least one slab whole body heater 125, which increases the cross section temperature of the slab 100, and at least one slab width end heater 120, which increases the end portion in the width direction of the slab 100, are alternately arranged. Here, the slab width end heater 120, which is arranged closest to the in-side, is arranged at a position closer to the in-side than the slab whole body heater 125, but the arrangement order of the slab width end heater 120 and the slab whole body heater 125 can also be reversed.

[0118] As the slab whole body heater 125, a longitudinal heating coil type, a transverse heating coil type, or the like is used.

[0119] The control device 90 also adjusts the output of the slab width end heater 120 and the slab whole body heater 125 based on the temperature difference between the front end temperature and the rear end temperature of the slab 100 measured by the first temperature increasing device in-side thermometer 202, and the conveyance speed of the slab 100.

[0120] For example, the control device 90 switches the conveyance direction of the slab 100 after the rear end of the slab 100 passes the slab width end heater 120 of the foremost row (the most upstream side in the conveyance direction), so that the slab 100 repeatedly moves back and forth inside the slab whole body heater 125 and the slab width end heater 120, and when the surface temperature measured by the first temperature increasing device in-plant thermometer 201 reaches a pre-set temperature or reaches a pre-set time, the temperature increase by the first induction heating slab heater 20 is completed and the slab 100 is conveyed outside the first induction heating slab heater 20.

[0121] Here, in the first induction heating slab heater 20, the slab 100 is heated while being swung (reciprocated) in the rolling direction. During the swing length L4, heating is performed by both the slab whole body heater 125 and the slab width end heater 120, and each slab whole body heater 125 and slab 100 end heater performs heating in each interval, so that the entire length of the slab 100 can be uniformly heated. There is a length L3 of the slab 100, which is the sum of the maximum slab length L2 and the swing length L4. The above lengths L2, L3, L4, L5 are appropriately set according to the user's requirements.

[0122] The side guides 110 are provided on the entry side and the exit side to determine the width direction position of the slab 100, and in addition, the device inner side guide 115 is provided between the slab overall heater 125 and the slab width end heater 120 to determine the width direction position of the slab 100. The device inner side guide 115 is appropriately set considering the minimum slab length or the like, and thus is not limited to Figure 12 .

[0123] Figure 13 represents the difference in the average temperature of the front end and the rear end of the slab 100. Figure 13 The horizontal axis represents the distance from the meniscus (the liquid surface in the mold), and the vertical axis represents the temperature of the slab 100. Each of the temperatures of the thickness center, the average temperature, and the surface temperature of the cast slab is described. Here, using the solidification calculation, the cast slab is set to advance at the same speed, the distance from the meniscus is the position of the cast slab, and the temperature of the cast slab at the position is shown.

[0124] The slab 100 advances at the casting speed until it is divided into the slab 100 by the flame cutting machine 14 after passing through the exit of the continuous casting machine 12. When the rear end is cut off by the flame cutting machine 14, the front end advances by the length of the slab 100 at the casting speed, and thus the temperature of the front end of the slab 100 is lower than that of the rear end.

[0125] When the length of the slab 100 is set to 12 m, the average temperature of the front end of the slab 100 after being divided by the flame cutting machine 14 is 1075°C, and the average temperature of the rear end of the slab 100 is 1125°C. In this case, the difference in the average temperature of the front end and the rear end is 50°C.

[0126] Figure 14 is a graph illustrating a method of eliminating the temperature difference between the front end and the rear end of the slab 100. The process of eliminating the temperature difference between the front end and the rear end or setting it to a desired temperature difference is called temperature difference compensation heating. This compensation superheating can be performed by either of the first temperature raising device and the second temperature raising device, and preferably, both of them.

[0127] When the moving length of the slab 100 is set to L6, heating is started from the front end of the slab 100 using the induction heating slab heater when the front end of the slab 100 reaches the entrance of the induction heating slab heater.

[0128] The heating is continued while the slab 100 is transported at the speed Vs, and when the rear end just reaches the entrance of the induction heating slab heater, the speed Vs and the output of each of the heaters of the induction heating slab heater are adjusted so that the temperature difference is eliminated or becomes a desired temperature difference.

[0129] And, after the temperature difference between the leading end and the trailing end is eliminated or set to a desired temperature difference, the slab 100 is swung in the induction heating slab heater while heating the entire slab 100.

[0130] In Figure 13 , in a case where the length of the slab 100 is 12 m and the temperature difference between the leading end and the trailing end is 50°C, the temperature difference of 50°C can be eliminated or minimized by performing the above-described temperature difference compensation heating.

[0131] Figure 15 is a view illustrating a case where the direct rolling is performed by heating the slab 100 only with the first induction heating slab heater 20 without using the second induction heating slab heater 22.

[0132] In a case where the casting speed is low at 1.2 m / min, three times of heating is required as shown in Figure 6 .

[0133] The rolling apparatus 1A in which the first induction heating slab heater 20 and the first heat retaining device 30 of at least three groups are arranged in series as shown in Figure 15 does not use the second induction heating slab heater 22, the second heat retaining device 32, and the third heat retaining device 34 outside the rolling line, and can perform the heating only with the first induction heating slab heater 20 of the rolling line.

[0134] In a case where the casting speed is faster than 1.2 m / min, two first induction heating slab heaters 20 can also be provided depending on the capacity of the first induction heating slab heater 20.

[0135] Here, Figure 15 , the first induction heating slab heater 20 is provided with three, and the second induction heating slab heater 22 is provided with one, for a total of four induction heating slab heaters, but in the mode described in Figure 1 , Figure 6 , one first induction heating slab heater 20 and one second induction heating slab heater 22 can be provided for a total of two, so that the reduction of equipment cost can be achieved.

[0136] In addition, in the mode described in Figure 1 , Figure 6 , compared to the mode described in Figure 15 , the overall length of the equipment from the continuous casting machine 12 to the underground coiler 85 can be shortened, and the equipment can be made more compact. Further, in a case where the amount of the slab 100 supplied from the continuous casting machine 12 is large, two of the first induction heating slab heater 20 and two of the second induction heating slab heater 22 are provided, and the first slab conveyance device 40 and the like can be used to heat the slab with both the first induction heating slab heater 20 and the second induction heating slab heater 22, so that a large amount of the slab can be warmed to a desired temperature with a short facility. The number of the first induction heating slab heater 20 and the second induction heating slab heater 22 is appropriately determined in correspondence with the production demand of the user.

[0137] Figure 16 is a view showing an example of a general facility in which the slab 100 is inserted into a reheating furnace and heated. In a rolling facility, there are a facility provided with one reheating furnace 145 and a facility provided with a plurality of reheating furnaces 145.

[0138] Figure 17 is a view of a rolling facility provided with the slab 100 warming device of the present application in a general facility in which the slab 100 is inserted into a reheating furnace and heated. Figure 17 The arrow of indicates a flow of the slab 100 heated with the second induction heating slab heater 22 and the first induction heating slab heater 20 and then conveyed to a rolling facility.

[0139] In the rolling facility provided with the warming device of the present application as described above, in a case where the temperature of the slab 100 is low, the slab is caused to pass through the second induction heating slab heater 22 and the first induction heating slab heater 20 again after being heated with the second induction heating slab heater 22 and the first induction heating slab heater 20, so that a large amount of warming can be obtained. Further, the slab can be conveyed by the path of, and heated with the first induction heating slab heater 20 after being heated with the second induction heating slab heater 22 a plurality of times. Figure 17 Figure 9 In the rolling facility provided with the warming device of the present application as described above, in a case where the temperature of the slab 100 is low, the slab is caused to pass through the second induction heating slab heater 22 and the first induction heating slab heater 20 again after being heated with the second induction heating slab heater 22 and the first induction heating slab heater 20, so that a large amount of warming can be obtained. Further, the slab can be conveyed by the path of, and heated with the first induction heating slab heater 20 after being heated with the second induction heating slab heater 22 a plurality of times.

[0140] Although not shown, a method of entering a reheating furnace before and after heating with the first induction heating slab heater 20 and the second induction heating slab heater 22 can also be employed.

[0141] Further, in a case where it is necessary to maintain the slab 100 in a high-temperature state for a long time of several hours or the like, a reheating furnace is sometimes selected.

[0142] Generally, the amount of CO2 emission from a reheating furnace is large. In the warming device of the present application, however, by heating with the first induction heating slab heater 20 and the second induction heating slab heater 22, direct emission of CO2 can be reduced, so that the production of green steel is facilitated.

[0143] ​Further, by providing the reheating furnace as a furnace using electric power, a furnace of a mode in which CO2 emission is small, and combining the reheating furnace with the first induction heating slab heater 20 and the second induction heating slab heater 22, production of green steel can be performed.

[0144] Next, using Figure 18 to Figure 20 Another example of the structure of the first induction heating slab heater 20 and the second induction heating slab heater 22 will be described. Figure 18 and Figure 19 a front view of the induction heating slab heater is shown, Figure 20 a view in the A-A arrow direction of Figure 12 is shown.

[0145] In the case of the configuration shown in Figure 12 , in the length L3 of the slab 100 in which the slab width end heater 120 is provided, the slab width end heater 120 is provided alternately with the slab overall heater 125, but in Figure 18 , the slab width end heater 122 is provided in a position outside the length L3 of the slab 100 in which the slab overall heater 125 is provided in a position on the outlet side.

[0146] In this case, the control device 90 also switches the transport direction of the slab 100 so that the slab 100 repeatedly reciprocates inside the slab overall heater 125 until the surface temperature measured by the first temperature-in-riser thermometer 201 reaches a preset temperature, and after the surface temperature measured by the first temperature-in-riser thermometer 201 reaches the preset temperature or reaches a preset time, the slab 100 is transported to the slab width end heater 122.

[0147] Since the width end of the slab 100 is also heated when the slab 100 is heated while being swung by the slab overall heater 125, when the slab 100 is transported to the outlet side after the heating of the entire slab 100 is completed, the width end of the slab 100 is heated while the slab 100 is transported at an arbitrary speed.

[0148] Figure 18 The slab width end heater 122 of Figure 12 is provided with the same configuration as the slab width end heater of

[0149] When the slab width end heater 122 is provided on the outlet side as in Figure 18 , the heating deficiency of the width end of the slab 100 that occurs due to the heating by the slab overall heater 125 can be compensated for. Since the heating of the width end of the slab 100 can be adjusted after the slab overall is heated, the heating of the width end of the slab 100 with good precision can be performed.

[0150] In addition, in Figure 12 , a side guide is provided on the roller table 130, but the side guide can be disposed between the roller tables 130 without changing the swing length L4. In the case where the side guide is provided on the roller table 130, the equipment is overlapped and the configuration is complicated, but by disposing the side guide between the roller tables 130, the equipment can be simplified.

[0151] Further, as Figure 19 , the slab width end heater 121 can be provided on the entry side of the length L3 of the slab 100, and the heating of the width end is performed before the entire slab 100 is heated.

[0152] In the case where the slab width end heater 121 is provided on the entry side as in this Figure 19 , the heating of the width end of the slab 100 is completed before the entire cross section of the front end of the slab 100 is heated. As Figure 14 indicated, the slab 100 is conveyed at a relatively low speed when the temperature difference compensation heating is performed, and therefore the width end of the slab 100 is also heated under this condition, and therefore it is not necessary to provide a special time to heat the width end of the slab 100.

[0153] Further, in the case where the heat retaining device is provided on the exit side of the inductive slab heater (the first heat retaining device 30, the third heat retaining device 34), the entire heating and the uniform heating of the cross section of the slab 100 after the width end is heated can be performed using the heat retaining device.

[0154] In addition, the disposition of the device inner side guide 115 between the slab entire heaters 125 is appropriately set in consideration of the minimum slab length and the like, and is not limited to Figure 18 . In addition, in Figure 18 and Figure 19 , the slab entire heater 125 and the slab width end heater 120 can be alternately disposed.

[0155] In Figure 20 , as the slab entire heater 125, a longitudinal heating coil type is used. Figure 20 The solid line indicates the position of the slab width end heater when the slab is wide. The dotted line indicates the position of the slab width end heater when the slab is narrow, and in this case, the dotted line only shows the position of the slab width end heater on the right side when the slab is narrow, and the position of the slab width end heater on the left side is also set to the same position as the right side.

[0156] In order to cope with the maximum width wide slab 100A and the minimum width narrow slab 100B, the position of the slab width end heater 120 is changed in the width direction to be set at a position suitable for heating the width end of the slab 100 according to the width of the slab 100. Also, the positions of the slab width end heaters 121, 122 are changed in the width direction.

[0157] With respect to the width of the slab 100, for example, a wide range of 900 mm to 1600 mm or the like is available. When the width of the slab 100 changes, the heating state of the width end of the slab 100 by the slab overall heater 125 also changes. For this reason, the heating of the width end of the slab 100 can be adjusted according to the width of the slab 100 by the slab width end heaters 120, 121, 122.

[0158] In addition, the position of the width direction of the device inner side guide 115 through which the slab 100 passes can be set so that the width end of the slab 100 does not interfere with the slab width end heaters 120, 121, 122.

[0159] Next, the effects of the present embodiment will be described.

[0160] Conventionally, when a failure occurs after the rough rolling mill 70, the continuous casting machine 12 cannot be immediately stopped, and thus it is necessary to discharge the cast slab 100 outside the rolling line. In addition, depending on the slab 100, sometimes surface finishing is required before rolling due to a surface quality problem, and in this case, it is also necessary to discharge the slab 100 outside the rolling line.

[0161] The discharged slab 100 sometimes decreases in temperature to room temperature at the slab storage place 50 outside the rolling line. In the case where the slab 100 whose temperature has decreased to room temperature is heated again by the induction heating slab heater, a long time is required, and the ability to heat the discarded slab 100 again and return it to the rolling line is insufficient. Therefore, a large number of induction heating slab heaters are required.

[0162] In the temperature raising device for raising the temperature of the slab 100 of steel cast by the continuous casting machine 12 according to the present embodiment described above, the first temperature raising device is provided on the rolling line between the continuous casting machine 12 and the rough rolling machine 70, the second temperature raising device is provided on the temperature raising line different from the rolling line, the first slab conveyance device 40 is configured to move the slab 100 between the exit side of the slab 100 on the rolling line of the first temperature raising device and the entry side of the slab 100 on the temperature raising line of the second temperature raising device, the second slab conveyance device 42 is configured to move the slab 100 between the entry side of the slab 100 on the rolling line of the first temperature raising device and the exit side of the slab 100 on the temperature raising line of the second temperature raising device, the first temperature raising device has the first induction heating slab heater 20, and the second temperature raising device has the second induction heating slab heater 22.

[0163] In the method for raising the temperature of the slab 100 of steel cast by the continuous casting machine 12, the slab 100 is raised in temperature by induction heating in the rolling line between the continuous casting machine 12 and the rough rolling machine 70, the slab 100 is raised in temperature by induction heating in the temperature raising line different from the rolling line, the slab 100 is moved between the heated rear side of the slab 100 on the rolling line and the heated front side of the slab 100 on the temperature raising line, and the slab 100 is moved between the heated front side of the slab 100 on the rolling line and the heated rear side of the slab 100 on the temperature raising line.

[0164] By using the induction heating slab heaters in combination, in the case where the temperature of the cast slab coming out of the first temperature raising device does not reach the desired temperature, the cast slab can be raised in temperature by the second temperature raising device until the cast slab is conveyed again to the first temperature raising device via the conveyance device, and thus the heating by the second temperature raising device can compensate for the deficiency in the temperature rise by the heating by the first temperature raising device. As a result, even the slab 100 cast at a slow casting speed can be raised in temperature to the desired temperature, and direct rolling can be performed.

[0165] In addition, by using the induction heating slab heaters described above in combination, even in the heating of the slab 100 to be discarded starting from room temperature, the slab 100 can be raised in temperature to the desired temperature for rolling with a smaller number of induction heating slab heaters.

[0166] In addition, the first temperature raising device further has the first heat retaining device 30 provided on the exit side of the slab 100 on the rolling line of the first induction heating slab heater 20, and the retained heat of the slab 100 is used as a heat source, and thus, compared to the case where the slab 100 is heated only by induction heating, the time during which the slab 100 stays in the induction heating device can be shortened. As a result, the time interval until the start of the heating of the next slab 100 by the induction heating device can be shortened.

[0167] Further, the second temperature raising device also has a second heat retaining device 32 and a third heat retaining device 34 provided at at least one of the entry side or the exit side of the slab 100 on the temperature raising line of the second induction heating slab heater 22, which uses the retained heat of the slab 100 as a heat source, so that the time for which the slab 100 stays in the induction heating device can be shortened compared to the case where the slab 100 is heated only by induction heating.

[0168] Further, at least one of a third slab conveyance device 44 configured to move the slab 100 between the slab storage place 50 storing the slab 100 and the entry side of the slab 100 on the temperature raising line of the second temperature raising device, and a fourth slab conveyance device 46 configured to move the slab 100 between the slab storage place 50 and the exit side of the slab 100 on the temperature raising line of the second temperature raising device is provided, so that flexible conveyance of the slab 100 between the slab storage place 50, the second temperature raising device, and the first temperature raising device can be achieved in accordance with the rolling conditions on the rolling line.

[0169] Further, a first temperature raising device internal thermometer 201 provided in the first temperature raising device to measure the temperature of the slab 100, and a control device 90 to determine which of the rough rolling mill 70 or the second temperature raising device to convey the slab 100 to, and switch the direction of conveyance of the slab 100 based on the temperature of the slab 100 measured by the first temperature raising device internal thermometer 201, so that it is determined whether to perform direct rolling or to additionally raise the temperature using the second induction heating slab heater 22, are provided, so that more reliable temperature raising can be achieved.

[0170] Further, the second temperature raising device has a second temperature raising device internal thermometer 203 to measure the temperature of the slab 100, and the second heat retaining device 32 and the third heat retaining device 34 provided at at least one of the entry side or the exit side of the slab 100 on the temperature raising line of the second induction heating slab heater 22, which uses the retained heat of the slab 100 as a heat source, and a control device 90 to determine the number of times of use and the residence time of the second induction heating slab heater 22 and the second heat retaining device 32 and the third heat retaining device 34 of the slab 100 in the second temperature raising device based on the temperature measured by the second temperature raising device internal thermometer 203 and the rolling conditions on the rolling line, and switch the direction of conveyance of the slab 100, so that additional temperature raising using the second induction heating slab heater 22 can also be performed more efficiently.

[0171] Further, the second temperature raising device has a second temperature raising device inside temperature gauge 203 which measures the temperature of the slab 100, and a second heat retaining device 32 and a third heat retaining device 34 which are provided at least one of the entry side or the exit side of the slab 100 on the temperature raising line of the second induction heating slab heater 22, and which use the retained heat of the slab 100 as a heat source, and further has a storage place temperature gauge 205 which is provided at the slab storage place 50 where the slab 100 is stored, and which measures the temperature of the slab 100, and a control device 90 which determines the number of times of use and the residence time of the second induction heating slab heater 22 and the second heat retaining device 32 and the third heat retaining device 34 of the slab 100 in the second temperature raising device based on the temperature of the slab 100 measured by the second temperature raising device inside temperature gauge 203, the temperature of the slab 100 in the slab storage place 50 measured by the storage place temperature gauge 205, and the rolling condition on the rolling line, and switches the direction of conveyance of the slab 100, thereby enabling more efficient heating of the slab 100 which has been stored in the slab storage place 50.

[0172] Further, the second temperature raising device has a second heat retaining device 32 and a third heat retaining device 34 which are provided at least one of the entry side or the exit side of the slab 100 on the temperature raising line of the second induction heating slab heater 22, and which use the retained heat of the slab 100 as a heat source, and further has a control device 90 which controls the conveyance of the slab 100 so as to heat different slabs 100 by the second induction heating slab heater 22 while the slab 100 is being heat retained by the second heat retaining device 32 and the third heat retaining device 34, thereby enabling heating of a plurality of slabs 100 without waste and efficiently while minimizing the risk of exceeding the upper limit temperature.

[0173] Further, the first induction heating slab heater 20 has at least one slab whole body heater 125 which raises the cross section temperature of the slab 100, or has at least one slab width end heater 120 which raises the end portion in the width direction of the slab 100 and at least one slab whole body heater 125 which raises the cross section temperature of the slab 100, and further has a first temperature raising device entry side temperature gauge 202 which is provided at the entry side of the slab 100 on the rolling line of the first temperature raising device, and which measures the surface temperature of the slab 100, and a control device 90 which adjusts the output of the slab width end heater 120 or the slab whole body heater 125 based on the temperature difference between the front end temperature and the rear end temperature of the slab 100 measured by the first temperature raising device entry side temperature gauge 202 and the conveyance speed of the slab 100, thereby enabling reduction of the temperature difference between the front end and the rear end in the rolling direction of the slab 100, and thus enabling more uniform heating of the slab 100.

[0174] In addition, the temperature rising device further comprises a first temperature sensor 201 arranged in the first temperature rising device to measure the temperature of the slab 100, the slab width end heater 120 and the slab overall heater 125 are arranged alternately, after the rear end of the slab 100 enters the first induction heating slab heater 20, the control device 90 switches the conveying direction of the slab 100 to make the slab 100 repeatedly reciprocate in the first induction heating slab heater 20, after the surface temperature measured by the first temperature sensor 201 reaches a preset temperature or reaches a preset time, the control device 90 completes the temperature rising by the first induction heating slab heater 20 and conveys the slab 100 out of the first induction heating slab heater 20, so that the heating of the rolling direction of the slab 100 can be more uniform.

[0175] In addition, the temperature rising device further comprises a first temperature sensor 201 arranged in the first temperature rising device to measure the temperature of the slab 100, the slab width end heater 120 and the slab overall heater 125 are arranged alternately, after the rear end of the slab 100 enters the first induction heating slab heater 20, the control device 90 switches the conveying direction of the slab 100 to make the slab 100 repeatedly reciprocate in the first induction heating slab heater 20, after the surface temperature measured by the first temperature sensor 201 reaches a preset temperature or reaches a preset time, the control device 90 completes the temperature rising by the first induction heating slab heater 20 and conveys the slab 100 out of the first induction heating slab heater 20, so that the heating of the rolling direction of the slab 100 can be more uniform.

[0176] Further, the above-described heating device is provided with a first heating device inside temperature gauge 201 which is provided in the first heating device to measure the temperature of the slab 100, and a slab width end portion heater 122 which is provided at the outlet side of the first induction heating slab heater 20, and the control device 90 switches the transport direction of the slab 100 so that the slab 100 repeatedly moves back and forth inside the first induction heating slab heater 20 until the surface temperature measured by the first heating device inside temperature gauge 201 reaches a predetermined temperature or a predetermined time elapses, and after the surface temperature measured by the first heating device inside temperature gauge 201 reaches the predetermined temperature or the predetermined time elapses, the slab 100 is transported to the slab width end portion heater 122 provided at the outlet side of the first induction heating slab heater 20 to heat the width end portion of the slab 100, so that the heating of the width end portion of the slab 100 can be performed after the entire slab is heated, and thus the width end portion of the slab 100 can be heated with high precision.

[0177] (Other) In addition, the present application is not limited to the above-described embodiments, and various modifications and applications can be made. The above-described embodiments are described in detail for the purpose of facilitating the understanding of the present application, and are not necessarily limited to having all the structures described.

[0178] For example, the slab transport device which transports the slab 100 between the rolling line and a line different from the rolling line is illustrated so as to make the slab 100 travel horizontally, but a method in which the transport table is rotated at an arbitrary angle to transport the slab, a method in which the slab is transported using the roller table 130 after being rotated using the turntable, and other methods are also included in the present application. In addition, a structure in which a heating device is provided in the transport device and the rotated transport table to suppress the temperature decrease of the slab during transport is also included in the present application. In addition, the slab width end portion heater and the entire slab heater of the second heating device are provided in the same structure as the first heating device, which is also included in the present application.

[0179] In addition, the continuous casting machine 12 is described as being provided in a two-stream configuration, but a one-stream case, and a case in which the continuous casting machine is additionally provided to be provided in more streams are also within the scope of the present application. In a case in which the production amount on the continuous casting machine 12 side is increased, the capacity of the first induction heating slab heater 20 and the second induction heating slab heater 22 is increased in accordance with the production amount, or the number of induction heating slab heaters is increased, but these are within the scope of the present application. Explanation of Reference Numerals

[0180] 1, 1A, rolling mill; 10, ladle turret; 12, continuous caster; 14, flame cutting machine; 20, 1st induction heating slab heater (induction heating device); 22, 2nd induction heating slab heater (induction heating device); 30, 1st heat retaining device (heat retaining device); 32, 2nd heat retaining device (heat retaining device); 34, 3rd heat retaining device (heat retaining device); 40, 1st slab conveyer (1st conveyer); 42, 2nd slab conveyer (2nd conveyer); 44, 3rd slab conveyer (3rd conveyer); 46, 4th slab conveyer (4th conveyer); 48, slab conveyer on the exit side of the continuous caster; 50, slab storage site; 60, scale remover; 70, roughing mill; 75, finishing mill train; 80, output roller table; 85, underground coiler; 90, control device; 100, slab; 100A, wide slab; 100B, narrow slab; 101, 1st slab; 102, 2nd slab; 103, 3rd slab; 104, 4th slab; 105, 5th slab; 110, side guide; 115, in-device side guide; 120, slab width end heater (width end heater); 121, slab width end heater (entry side width end heater); 122, slab width end heater (exit side width end heater); 125, slab overall heater (overall heater); 130, roller table; 145, reheating furnace; 201, 1st in-temperature device temperature gauge; 202, 1st entry side temperature gauge; 203, 2nd in-temperature device temperature gauge; 205, storage site temperature gauge; 301, conveyance table; 302, conveyance table; 304, conveyance table.

Claims

1. A heating device for heating a steel billet obtained by continuous casting, wherein, The heating device includes: The first heating device is located on the rolling line between the continuous casting machine and the roughing mill; The second heating device is located on a heating line different from the rolling line; A first conveying device is configured to move the billet between the exit side of the billet on the rolling line of the first heating device and the inlet side of the billet on the heating line of the second heating device; and The second conveying device is configured to move the billet between the inlet side of the billet on the rolling line of the first heating device and the outlet side of the billet on the heating line of the second heating device. The first heating device and the second heating device have induction heating devices.

2. The heating device according to claim 1, wherein, The first heating device also includes a heat preservation device, which is located on the exit side of the billet on the rolling line of the induction heating device, and uses the heat of the billet as a heat source.

3. The heating device according to claim 1, wherein, The second heating device also includes a heat preservation device, which is disposed on at least one of the inlet or outlet side of the billet on the heating line of the induction heating device, and uses the heat retained by the billet as a heat source.

4. The heating device according to claim 1, wherein, The heating device further includes at least one of a third conveying device and a fourth conveying device. The third conveying device is configured to move the billet between the storage location where the billet is stored and the inlet side of the billet on the heating line of the second heating device, and the fourth conveying device is configured to move the billet between the storage location and the outlet side of the billet on the heating line of the second heating device.

5. The heating device according to any one of claims 1 to 4, wherein, The heating device also includes: A thermometer is installed in the first heating device to measure the temperature of the cast billet; and A control device, based on the temperature of the billet measured by a thermometer in the first heating device, determines whether the billet should be fed to the roughing mill or the second heating device, and switches the feeding direction of the billet.

6. The heating device according to any one of claims 1, 2, and 4, wherein, The second heating device includes an internal thermometer and a heat preservation device. The internal thermometer measures the temperature of the cast billet. The heat preservation device is located on at least one of the inlet or outlet side of the cast billet on the heating line of the induction heating device, using the retained heat of the cast billet as a heat source. The heating device also includes a control device, which determines the number of times the induction heating device and the heat preservation device of the billet at the second heating device are used and the dwell time is based on the temperature measured by the thermometer in the second heating device and the rolling condition on the rolling line, and switches the conveying direction of the billet.

7. The heating device according to claim 1 or 2, wherein, The second heating device includes an internal thermometer and a heat preservation device. The internal thermometer measures the temperature of the cast billet. The heat preservation device is located on at least one of the inlet or outlet side of the cast billet on the heating line of the induction heating device, using the retained heat of the cast billet as a heat source. The heating device also includes: A storage location thermometer, installed in the storage location where the cast billet is stored, measures the temperature of the cast billet; and The control device determines the number of times the induction heating device and the heat preservation device of the billet at the second heating device are used and the dwell time is based on the temperature of the billet measured by the thermometer in the second heating device, the temperature of the billet at the storage location measured by the thermometer in the storage location, and the rolling status on the rolling line, and switches the conveying direction of the billet.

8. The heating device according to any one of claims 1, 2, and 4, wherein, The second heating device includes a heat preservation device, which is disposed on at least one of the inlet or outlet side of the billet on the heating line of the induction heating device, and uses the retained heat of the billet as a heat source. The heating device also includes a control device that controls the conveying of the billet, so as to heat different billets using the induction heating device while the billet is kept warm by the heat preservation device.

9. The heating device according to any one of claims 1 to 4, wherein, The induction heating device has at least one integral heater for heating the cross-section of the billet, or at least one width end heater for heating the end of the billet in the width direction and at least one integral heater for heating the cross-section of the billet. The heating device also includes: A first heating device inlet thermometer, located on the inlet side of the billet on the rolling line of the first heating device, measures the surface temperature of the billet; and A control device that adjusts the output of the width end heater or the overall heater based on the temperature difference between the front and rear ends of the billet measured by the thermometer at the inlet side of the first heating device and the conveying speed of the billet.

10. The heating device according to claim 9, wherein, The heating device also includes a first heating device internal thermometer, which is installed in the first heating device to measure the temperature of the cast billet. The wide-end heaters and the overall heaters are arranged alternately. After the rear end of the billet enters the induction heating device, the control device switches the conveying direction of the billet so that the billet repeatedly reciprocates inside the induction heating device. After the surface temperature measured by the thermometer in the first heating device reaches a preset temperature or a preset time, the control device completes the heating performed by the induction heating device and transports the billet outside the induction heating device.

11. The heating device according to claim 9, wherein, The heating device also includes: A thermometer is installed in the first heating device to measure the temperature of the cast billet; and An inlet-side width end heater is disposed on the inlet side of the induction heating device. The control device heats the wide end of the billet as it passes through the inlet-side wide-end heater. When the rear end of the billet enters the induction heating device, the control device switches the billet's conveying direction, causing the billet to repeatedly reciprocate within the induction heating device. After the surface temperature measured by the thermometer in the first heating device reaches a preset temperature or a preset time, the control device completes the heating performed by the induction heating device and transports the billet outside the induction heating device.

12. The heating device according to claim 9, wherein, The heating device also includes: A thermometer is installed in the first heating device to measure the temperature of the cast billet; and An outlet-side width end heater is disposed on the outlet side of the induction heating device. The control device switches the conveying direction of the billet, causing the billet to reciprocate repeatedly inside the induction heating device until the surface temperature measured by the thermometer in the first heating device reaches a preset temperature or a preset time. After the surface temperature, as measured by the thermometer in the first heating device, reaches a preset temperature or a preset time, the control device conveys the billet to the outlet-side width end heater to heat the width end of the billet.

13. A rolling mill, wherein, The rolling equipment includes: The continuous casting machine; The heating device according to any one of claims 1 to 4; and Roughing mill.

14. A heating method for heating the cast billet using the heating device according to any one of claims 1 to 4, wherein, The billet is heated by induction heating within the rolling line. The billet is heated by induction heating within the heating line. The billet is moved between the heated rear side of the billet on the rolling line and the heated front side of the billet on the heating line. The billet is moved between the front side of the billet on the rolling line and the rear side of the billet on the heating line.

15. A heating method for heating the billet using the heating device according to any one of claims 1 to 4, wherein, The heating method is performed alternately: In the first step, the billet is heated by induction heating in the rolling line and then transported to the roughing mill. as well as In the second step, the different billets are transported to the heating line using the second conveying device. After the different billets are heated by induction heating in the heating line, the different billets are transported to the rolling line using the first conveying device.

Images