JP7719355B2 - Cylindrical metal coil processing equipment - Google Patents

Description

The present invention relates to processing equipment for cylindrical metal coils.

High-alloy steels, such as high-tensile steel, electrical steel, and stainless steel, often have low toughness at low temperatures. When such high-alloy steel sheets are wound into a cylindrical coil, bending stress occurs when the steel sheet is deformed from its coiled shape to a flat shape during unwinding for processes such as rolling and continuous annealing, which can lead to cracking. Therefore, it is necessary to heat the coil to above its brittle temperature, at which point toughness increases, before unwinding. This heating is performed by batch heating the entire coil in, for example, a gas furnace or electric furnace. However, heating the entire coil requires time for the heat applied to the surface to be transferred to the interior, which reduces production efficiency.

In response to the above-mentioned problems with batch heating of metal coils, the technology described in Patent Document 1 uses a box-shaped preheating device that surrounds the reel drum (winding core) of the payoff reel and the coil as one of the heating devices within the cold rolling equipment, installed 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 the heating device, and then passed through the rolling mill. By transporting the coil to the payoff reel immediately after the previous process and then undergoing the above-mentioned preheating and heating process before undergoing rolling, it is possible to prevent cracking of the steel sheet while performing rolling without using a batch heating device.

JP 2011-79025 A

In the preheating device described in Patent Document 1 above, the heating device is a box-type device that surrounds the reel drum and coil of the payoff reel. As a result, the inner and outer layers of the coil are primarily heated, and a considerable amount of processing time is required to heat the entire coil to the specified temperature, so process constraints still exist.

The present invention aims to provide cylindrical metal coil processing equipment that can prevent cracking of metal bands when unwinding them from cylindrical metal coils while minimizing process constraints.

[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 peripheral surface of the cylindrical metal coil near the location where the metal band is unwound from the cylindrical metal coil and to generate eddy currents on the surface of the cylindrical metal coil; a control means for controlling the frequency of an 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 plate, and a heating device for heating the metal band plate between the unwound means and the winding means.
[5] The cylindrical metal coil treatment equipment according to [4], wherein the heating device includes an induction coil arranged to generate eddy currents in the metal strip.

With the above configuration, the eddy currents generated by the induction coil heat the metal strip just before it is unwound from the cylindrical metal coil. Induction heating allows heating to the desired temperature regardless of the temperature of the cylindrical metal coil before heating, eliminating process constraints such as those associated with offline batch heating and online box heating. Therefore, with the above configuration, process constraints can be minimized while preventing cracks in the metal strip when it is unwound from the cylindrical metal coil.

1 is a diagram showing a schematic configuration of a cylindrical metal coil processing facility according to a first embodiment of the present invention; 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. 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.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Note that in this specification and drawings, components that have substantially the same functional configuration will be assigned the same reference numerals, and redundant explanations will be omitted.

(First embodiment)
1 is a diagram showing a 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 12 (only the reel drum portion is shown, and other portions are not shown; the same applies below) constituting an unwinding means for unwinding the metal strip S from a cylindrical metal coil 11 having the metal strip S wound therearound 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.

Here, induction coil 13 faces the outer circumferential surface of cylindrical metal coil 11 near the location where metal strip S is unwound from cylindrical metal coil 11. In other words, induction coil 13 is positioned before position P where metal strip S separates from the outer circumferential surface of cylindrical metal coil 11 in the transport direction of unwound metal strip S. Induction coil 13 is, for example, a flat-wound coil positioned to generate magnetic flux in the radial direction of cylindrical metal coil 11, and generates eddy currents on the surface of cylindrical metal coil 11. Therefore, it is the metal strip S immediately before being unwound from cylindrical metal coil 11 that is heated by the eddy currents generated by induction coil 13.

Meanwhile, the high-frequency power supply 14 that supplies AC current to the induction coil 13 functions as a control means that controls the frequency of the AC current, for example, using 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 currents generated by the induction coil 13 in the surface layer of the cylindrical metal coil 11 corresponds to the thickness of the metal strip S. In this case, most of the eddy currents penetrate only one sheet of metal strip S, i.e., the outermost layer of the cylindrical metal coil 11, and therefore only the metal strip S in the outermost layer of the cylindrical metal coil 11 is actually heated.

As described above, the induction coil 13 heats essentially only the outermost layer of the metal strip S of the cylindrical metal coil 11, allowing for concentrated eddy current heating of the metal strip S just before it is unwound from the cylindrical metal coil 11. This makes it easier to heat the metal strip S to a temperature sufficient to prevent cracking in subsequent processes. The induction coil 13 may be positioned to heat the metal strip S uniformly across its entire width, or may be positioned to increase the temperature at the widthwise ends, where temperature drops are more likely to occur during transport.

Furthermore, if there is no insulating material inserted between the layers of the cylindrical metal coil 11 or no insulating scale formed, the occurrence of sparks due to interlayer short circuits can be substantially suppressed by limiting the range of heating due to eddy currents to essentially the outermost layer. On the other hand, if the layers of the cylindrical metal coil 11 are insulated 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, for example, 10 layers or less including the outermost layer.

The induction coil moving means 15 includes, for example, an air cylinder or electric cylinder as a drive unit, and moves the induction coil 13 radially around 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 metal strip S is unwound, and allows the metal strip S to be heated at a uniform temperature from the start to the end of unwinding without changing the AC power supplied to the induction coil 13.

The processing equipment 10 described above is equipment that performs, for example, rolling or continuous annealing of metal strip S. Although not shown, when performing rolling, 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 continuous annealing, 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.

Second Embodiment
FIG. 2 is a schematic 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 constituting 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 disposed 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.

In this embodiment, in addition to induction coil 13A, which faces the outer peripheral surface of cylindrical metal coil 11 near the location 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 peripheral surface of cylindrical metal coil 11 at locations different from induction coil 13A. Like induction coil 13 in the first embodiment, induction coils 13A, 13B, and 13C are also planar coils arranged to generate magnetic flux in the radial direction of cylindrical metal coil 11, and when supplied with frequency-controlled alternating current, generate eddy currents 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 electric cylinder as a driving unit, and move induction coils 13A, 13B, and 13C in accordance with changes in the outer diameter of cylindrical metal coil 11 due to unwinding.

The processing equipment 10A according to the second embodiment, as described above, is also equipment for performing, for example, rolling or continuous annealing of metal strip S, and further includes components such as a rolling mill or continuous annealing furnace (not shown). In this embodiment, by using multiple induction coils 13A, 13B, and 13C to heat the surface of the cylindrical metal coil 11 with eddy currents, it is possible to ensure sufficient heating time, which is expected to improve temperature controllability and processing capacity.

(Third embodiment)
FIG. 3 is a schematic 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 portion 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 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 are not shown in the figure. Also, in this embodiment, it is possible to configure the heating device 26 so that a plurality of induction coils are arranged, as in the second embodiment.

In this embodiment, the processing equipment 20 is equipment for performing 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 and rewound into the cylindrical metal coil 21 before being transported to the next process. This type of processing equipment 20 can be used as an alternative to an intermediate heating device that heats the entire cylindrical metal coil, such as a batch heat treatment furnace. Batch heating of a cylindrical metal coil in its wound state requires time for the heat applied to the surface to be transferred to the interior. However, the processing equipment 20 unwound the metal strip S and then directly heats the internal portion of the metal strip S while it is still in its cylindrical metal coil state. This shortens the time required to heat the entire coil compared to batch heating. Furthermore, it is possible to preheat the widthwise ends, 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, which is on the outer periphery of the coil after rewound, is higher.

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 it will crack when unwound, it is possible not to use the induction coil 13 or induction coil moving means 15.

The above describes in detail preferred embodiments of the present invention with reference to the accompanying drawings, but the present invention is not limited to these examples. It is clear that a person skilled in the art of the technology to which the present invention pertains could conceive of various modifications or alterations within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

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 (5)

an unwinding means for unwinding a metal band made of high alloy steel from a cylindrical metal coil in which the metal band 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;
and a moving means for moving the induction coil in the radial direction of the cylindrical metal coil in response to changes in the outer diameter of the cylindrical metal coil due to unwinding. The cylindrical metal coil processing equipment of claim 1 further comprises an additional induction coil positioned opposite the outer circumferential surface of the cylindrical metal coil at a location different from the induction coil and arranged to generate eddy currents on the surface of the cylindrical metal coil. The cylindrical metal coil processing equipment according to claim 1 or claim 2, further comprising a rolling mill or continuous annealing furnace for processing the unwound metal strip. a winding means for rewinding the unwound metal strip;
The cylindrical metal coil treatment facility according to claim 1 or 2, further comprising: a heating device for heating the metal band plate between the unwinding means and the winding means. The cylindrical metal coil processing equipment of claim 4, wherein the heating device includes an induction coil arranged to generate eddy currents in the metal strip.