Cylindrical metal coil processing equipment

Abstract

To prevent cracking of a metal strip and minimize constraints in a process when the metal strip is wound out from the cylindrical metal coil.SOLUTION: A cylindrical metal coil facility comprises: winding-out means for winding out a metal strip from a cylindrical metal coil having the metal strip cylindrically wound thereon; an induction coil opposed to the outer peripheral surface of the cylindrical metal coil in the vicinity of a part in which the metal strip is wound out from the cylindrical metal coil and disposed to generate eddy current on the surface layer of the cylindrical metal coil; control means for controlling a frequency of AC current supplied to the induction coil so that the penetration depth of the eddy current can correspond to the plate thickness of the metal strip; and movement means for moving the induction coil in the radial direction of the cylindrical metal coil following a change of the outer diameter of the cylindrical metal coil caused by the winding-out.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a treatment facility for cylindrical metal coils. [Background technology]

[0002] Many high-alloy steels, such as high-tensile steel, electrical steel, and stainless steel, have low toughness at low temperatures. When such high-alloy steel sheets are wound into a cylindrical coil, they can crack when unwound from the coil for processes such as rolling and continuous annealing. Therefore, it is necessary to heat the coil to a temperature above its brittleness temperature, at which point toughness increases, before unwinding. This heating is typically performed by batch heating the entire coil in a gas furnace or electric furnace, but heating the entire coil requires time for the heat applied to the surface to be transferred to the interior, reducing production efficiency.

[0003] In response to the above-mentioned problem of batch heating of metal coils, the technology described in Patent Document 1 uses a box-shaped preheating device as one of the heating devices in cold rolling equipment, which surrounds the reel drum (winding core) of the payoff reel and the coil at the payoff reel position where the coil is delivered to the rolling mill, and preheats the coil using a hot air heater. The steel sheet pulled out from the coil is passed through a straightener, further heated in a heating device, and then passed through the rolling mill. By transporting the coil to the payoff reel immediately after the previous process and performing the above-mentioned preheating and heating process before rolling, it is possible to perform the rolling process while preventing cracks in the steel sheet without using a batch heating device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-79025 Summary of the Invention [Problem to be solved by the invention]

[0005] In the preheating device described in the above Patent Document 1, the heating device is a box type that surrounds the reel drum and coil of the payoff reel, so the inner and outer layers of the coil are mainly heated, and it takes a certain amount of processing time to heat the entire coil to the specified temperature, so there are still process constraints.

[0006] Therefore, an object of the present invention is to provide a cylindrical metal coil processing facility that can prevent cracking of a metal band when unwinding the metal band from the cylindrical metal coil while minimizing process constraints. [Means for solving the problem]

[0007] [1] A cylindrical metal coil processing facility comprising: an unwinding means for unwinding a metal band from a cylindrical metal coil having the metal band wound cylindrically; an induction coil arranged to face the outer surface of the cylindrical metal coil near the location where the metal band is unwound from the cylindrical metal coil and generate eddy currents on the surface of the cylindrical metal coil; a control means for controlling the frequency of the alternating current supplied to the induction coil so that the penetration depth of the eddy current corresponds to the thickness of the metal band; and a moving means for moving the induction coil in the radial direction of the cylindrical metal coil in accordance with changes in the outer diameter of the cylindrical metal coil due to unwinding. [2] The cylindrical metal coil processing equipment described in [1] further comprises an additional induction coil that faces the outer peripheral surface of the cylindrical metal coil at a location different from the induction coil and is arranged to generate eddy currents on the surface of the cylindrical metal coil. [3] The cylindrical metal coil processing facility according to [1] or [2], further comprising a rolling mill or a continuous annealing furnace for processing the unwound metal strip. [4] The cylindrical metal coil processing equipment according to [1] or [2], further comprising a winding means for rewinding the unwound metal band, and a heating device for heating the metal band between the unwound means and the winding means. [5] The cylindrical metal coil processing equipment according to [4], wherein the heating device includes an induction coil arranged to generate eddy currents in the metal strip. [Effects of the Invention]

[0008] According to the above-described configuration, the metal strip is heated by eddy currents generated by the induction coil immediately before being unwound from the cylindrical metal coil. Since induction heating can heat the metal strip to a desired temperature regardless of the temperature of the cylindrical metal coil before heating, it eliminates process constraints such as those imposed by batch heating in offline processing and box heating in online processing. Therefore, according to the above-described configuration, cracks in the metal strip can be prevented when the metal strip is unwound from the cylindrical metal coil, while process constraints can be minimized. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing a schematic configuration of a cylindrical metal coil processing facility according to a first embodiment of the present invention. [Figure 2] FIG. 10 is a diagram showing a schematic configuration of a cylindrical metal coil processing facility according to a second embodiment of the present invention. [Figure 3] FIG. 10 is a diagram showing a schematic configuration of a cylindrical metal coil processing facility according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant explanations will be omitted.

[0011] (First embodiment) 1 is a diagram showing the schematic configuration of a cylindrical metal coil processing facility according to a first embodiment of the present invention. The processing facility 10 includes a payoff reel (only the reel drum portion is shown, and other portions are not shown; the same applies below) 12 constituting an unwinding means for unwinding a metal strip S from a cylindrical metal coil 11 having a metal strip S wound around it in a cylindrical shape, an induction coil 13 facing the outer circumferential surface of the cylindrical metal coil 11, a high-frequency power source 14 for supplying AC current to the induction coil 13, and an induction coil moving means 15 for moving the induction coil 13 in the radial direction of the cylindrical metal coil 11.

[0012] Here, the induction coil 13 faces the outer circumferential surface of the cylindrical metal coil 11 near the location where the metal strip S is unwound from the cylindrical metal coil 11. In other words, the induction coil 13 is disposed before a position P where the metal strip S moves away from the outer circumferential surface of the cylindrical metal coil 11 in terms of the conveyance direction of the unwound metal strip S. The induction coil 13 is, for example, a flat-wound coil disposed so as to generate magnetic flux in the radial direction of the cylindrical metal coil 11, and generates eddy currents on the surface layer of the cylindrical metal coil 11. Therefore, it is the metal strip S immediately before being unwound from the cylindrical metal coil 11 that is heated by the eddy currents generated by the induction coil 13.

[0013] Meanwhile, the high-frequency power supply 14 that supplies AC current to the induction coil 13 functions as a control means for controlling the frequency of the AC current, for example, by an inverter. The high-frequency power supply 14 controls the frequency of the AC power supplied to the induction coil 13 so that the penetration depth of the eddy current generated by the induction coil 13 in the surface layer of the cylindrical metal coil 11 corresponds to the thickness of the metal band S. In this case, most of the eddy current penetrates only one sheet of the metal band S, i.e., the outermost layer of the cylindrical metal coil 11, and therefore, only the metal band S at the outermost layer of the cylindrical metal coil 11 is actually heated.

[0014] As described above, the induction coil 13 heats substantially only the outermost layer of the metal band S of the cylindrical metal coil 11, thereby enabling the metal band S to be heated by concentrated eddy currents immediately before being unwound from the cylindrical metal coil 11. This makes it easy to heat the metal band S to a temperature sufficient to prevent cracking in subsequent processes. The induction coil 13 may be positioned so as to heat the metal band S uniformly across its entire width, or may be positioned so as to increase the amount of temperature rise at the widthwise ends where a temperature drop during transport is likely to occur.

[0015] Furthermore, if there is no insulating material or insulating scale between the layers of the cylindrical metal coil 11, the occurrence of sparks due to interlayer short circuits can be substantially suppressed by limiting the range of heating due to eddy currents to the outermost layer. On the other hand, if the layers of the cylindrical metal coil 11 are insulated from each other by insulating material or insulating scale, the range of heating due to eddy currents does not necessarily have to be limited to the outermost layer, and may be set to a range of 10 layers or less including the outermost layer, for example.

[0016] The induction coil moving means 15 includes, for example, an air cylinder or an electric cylinder as a drive unit, and moves the induction coil 13 in the radial direction of the cylindrical metal coil 11. The outer diameter of the cylindrical metal coil 11 gradually decreases as the metal strip S is unwound. The induction coil moving means 15 moves the induction coil 13 in accordance with this change in the outer diameter of the cylindrical metal coil 11. This maintains the gap between the outer surface of the cylindrical metal coil 11 and the induction coil 13 even as the unwinding of the metal strip S progresses, and enables the metal strip S to be heated at a uniform temperature from the start to the end of unwinding without changing the power of the alternating current supplied to the induction coil 13.

[0017] The processing equipment 10 as described above is equipment that performs, for example, a rolling process or a continuous annealing process on a metal strip S. Although not shown, when performing a rolling process, the processing equipment 10 includes components such as a rolling mill that processes the metal strip S unwound from the cylindrical metal coil 11 in addition to the components shown in FIG. 1 . When performing a continuous annealing process, the processing equipment 10 includes components such as a continuous annealing furnace that processes the metal strip S unwound from the cylindrical metal coil 11.

[0018] (Second embodiment) FIG. 2 is a diagram illustrating the configuration of a cylindrical metal coil processing facility according to a second embodiment of the present invention. Similar to the first embodiment, the processing facility 10A includes a payoff reel 12 that constitutes an unwinding means for unwinding a metal strip S from a cylindrical metal coil 11. In this embodiment, three induction coils 13A, 13B, and 13C are arranged facing the outer circumferential surface of the cylindrical metal coil 11. High-frequency power supplies that supply AC current to each induction coil and function as control means for controlling the frequency of the AC current are not shown. The processing facility 10A further includes induction coil moving means 15A, 15B, and 15C that move each of the induction coils 13A, 13B, and 13C radially around the cylindrical metal coil 11.

[0019] In this embodiment, in addition to induction coil 13A facing the outer circumferential surface of cylindrical metal coil 11 near the portion where metal strip S is unwound from cylindrical metal coil 11, as in the first embodiment, additional induction coils 13B and 13C are arranged facing the outer circumferential surface of cylindrical metal coil 11 at positions different from induction coil 13A. Like induction coil 13 in the first embodiment, induction coils 13A, 13B, and 13C are also flat-wound coils arranged to generate magnetic flux in the radial direction of cylindrical metal coil 11, and when supplied with frequency-controlled AC current, eddy currents are generated in the surface layer across the entire width of cylindrical metal coil 11. Induction coil moving means 15A, 15B, and 15C include, for example, an air cylinder or an electric cylinder as a driving unit, and move induction coils 13A, 13B, and 13C respectively in accordance with changes in the outer diameter of cylindrical metal coil 11 due to unwinding.

[0020] The processing equipment 10A according to the second embodiment as described above is also equipment for performing, for example, rolling or continuous annealing of a metal strip S, and further includes components such as a rolling mill or continuous annealing furnace (not shown). In this embodiment, the surface layer of the cylindrical metal coil 11 is heated by eddy current using multiple induction coils 13A, 13B, and 13C, thereby ensuring the heating time and expecting improved temperature controllability and processing capacity.

[0021] (Third embodiment) FIG. 3 is a diagram illustrating the configuration of a cylindrical metal coil processing facility according to a third embodiment of the present invention. Similar to the first embodiment, the processing facility 20 includes a payoff reel 12 constituting an unwinding means for unwinding the metal strip S from the cylindrical metal coil 11, an induction coil 13 facing the outer circumferential surface of the cylindrical metal coil 11 near the location where the metal strip S is unwound from the cylindrical metal coil 11, and an induction coil moving means 15 for moving the induction coil 13 radially around the cylindrical metal coil 11. In this embodiment, the processing facility 20 further includes a take-up reel (only the reel drum is shown, and other components are not shown; the same applies below) 22 constituting a winding means for rewinding the metal strip S unwound by the payoff reel 12 into a cylindrical metal coil 21, and a heating device 26 for heating the metal strip S between the payoff reel 12 and the take-up reel 22. The heating device 26 may be, for example, an induction coil arranged to generate eddy currents in the metal strip S. The illustration does not include the induction coil 13 and the high frequency power supply that functions as a control means for supplying AC current to the heating device 26 when the induction coil is used and controlling the frequency of the AC current. Also, in this embodiment, it is possible to configure the heating device 26 so that multiple induction coils are arranged, as in the second embodiment.

[0022] In this embodiment, the processing equipment 20 is equipment for performing a heat treatment on the metal strip S. The metal strip S is heated by the induction coil 13 when unwound from the cylindrical metal coil 11, then further heated in the heating device 26, rewound into the cylindrical metal coil 21, and transported to the next process. This processing equipment 20 can be used as an alternative to an intermediate heating device for heating the entire cylindrical metal coil, such as a batch heat treatment furnace. If the cylindrical metal coil is batch-heated while still in the wound state, it requires time for the heat applied to the surface to be transferred to the interior. However, in the processing equipment 20, the metal strip S is unwound once and the interior portion of the metal strip S can be directly heated. This shortens the time required to heat the entire coil compared to batch heating. Furthermore, it is possible to preheat the widthwise end portions, which are prone to temperature drop during transport, or to create a temperature gradient along the length of the metal strip S so that the temperature of the terminal end portion, which is located on the outer periphery of the coil after rewound, is higher.

[0023] In the example shown in Figure 3, an induction coil 13 is placed in the processing equipment 20 to heat the metal strip S near the location where it is unwound from the cylindrical metal coil 11. However, if the material of the metal strip S or the temperature of the cylindrical metal coil 11 when it is brought in from the previous process makes it unlikely that the metal strip S will crack when unwound, it is possible not to use the induction coil 13 and the induction coil moving means 15.

[0024] Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that a person skilled in the art to which the present invention pertains can conceive of various modifications or alterations within the scope of the technical ideas described in the claims, and it is understood that these also naturally fall within the technical scope of the present invention. [Explanation of symbols]

[0025] 10, 10A, 20... Processing equipment, 11... Cylindrical metal coil, 12... Payoff reel (reel drum), 13, 13A, 13B, 13C... Induction coil, 14... High frequency power supply, 15, 15A, 15B, 15C... Induction coil moving means, 21... Cylindrical metal coil, 22... Take-up reel (reel drum), 26... Heating device, S... Metal strip.

Claims

1. An unwinding means for unwinding a metal band plate made of high alloy steel from a cylindrical metal coil in which the metal band plate is wound in a cylindrical shape; an induction coil disposed opposite the outer circumferential surface of the cylindrical metal coil near the portion where the metal strip is unwound from the cylindrical metal coil, and arranged to generate eddy currents in the surface layer of the cylindrical metal coil; a control means for controlling the frequency of the AC current supplied to the induction coil so that the penetration depth of the eddy current corresponds to the thickness of the metal strip; a moving means for moving the induction coil in the radial direction of the cylindrical metal coil in accordance with a change in the outer diameter of the cylindrical metal coil due to unwinding; 1. A cylindrical metal coil processing facility comprising:

2. 2. The cylindrical metal coil processing equipment according to claim 1, further comprising an additional induction coil arranged to face the outer circumferential surface of the cylindrical metal coil at a location different from the induction coil and to generate eddy currents on the surface of the cylindrical metal coil.

3. 3. The cylindrical metal coil processing facility according to claim 1 or claim 2, further comprising a rolling mill or a continuous annealing furnace for processing the unwound metal strip.

4. a winding means for rewinding the unwound metal strip; a heating device for heating the metal band plate between the unwinding means and the winding means; The cylindrical metal coil processing facility according to claim 1 or claim 2, further comprising:

5. 5. The cylindrical metal coil treatment facility of claim 4, wherein the heating device includes an induction coil positioned to generate eddy currents in the metal strip.

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