JPH071023A - Induction heating method for plate materials - Google Patents

Abstract

PURPOSE:To greatly reduce the power to be used in the induction heating of plates in a method for induction heating of both edge parts of hot rolled plates, the parts to be joined of the front and rear edges or the like. CONSTITUTION:An inductor 4 is arranged on each edge part of advancing plates 2, and a filler plate 6 is inserted into the clearance of a C-shaped opening and the plates 2. The filler plate 6 to be used is made of a stock of small magnetic resistance, and of a structure with less iron loss and the plate thickness is t6. The high frequency current is applied to the inductors 4 and each edge part of the plates 2 is passed through the C-shaped opening of the inductors 4 to make the eddy current penetrate in the direction of the plate thickness of each edge part of the plates 2, and the magnetic flux concentratedly passes the area where the filler plate 6 is present, reduces the expansion of the magnetic flux, and the effective induction heating is executed only at the targetted part of the plates.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inductively heating both edges of a hot-rolled sheet material, joints of leading and trailing edges and the like with inductors.

[0002]

2. Description of the Related Art Conventionally, an induction heating method in which an eddy current is induced by a magnetic flux penetrating a plate material in the plate thickness direction to heat the plate material has been widely applied to an edge heater of a hot rolled plate material, a heating joining apparatus and the like.

FIG. 3 shows an example in which such an induction heating method is applied to an edge heater. The pair of inductors 4 arranged at both edge portions of the plate member 1 have substantially C-shaped openings. In order to avoid collision with the plate material 1, it is formed so as to form a minimum gap g ₁ with the lower surface and the upper surface of the plate material 1 having an allowable maximum plate thickness t ₁ , respectively.

Then, while passing the plate material 1 through the substantially C-shaped opening of the inductor 4, a magnetic flux is passed through in the plate thickness direction of the plate material 1 to induce an eddy current for induction heating, and both edge portions of the plate material 1 are heated. Prevents cooling.

[0005]

The distance t ₁ + 2g ₁ between the upper and lower portions of the substantially C-shaped opening of the inductor 4 in the conventional method for induction heating of both edges of the plate material as described above is constant.

[0006] However, the inductor 4 should correspond to the plate material of various thickness, for example, when the sheet material 2 having a thickness t _2, as shown by a two-dot chain line induction heating, the sheet material 2 thickness t ₂ Becomes smaller, the gap g ₂ becomes larger.

If the gap g ₂ is large (the space is long), the magnetic flux spreads to heat an unnecessarily wide area of the plate material 2 to lower the heating efficiency, and the air magnetic resistance of the space is large, resulting in loss of power. Causes a problem that the value becomes large.

The present invention has been proposed in order to solve the above-mentioned drawbacks of the prior art. Induction that reduces the spread of magnetic flux and reduces the magnetic resistance even if the gap between the plate material and the inductor becomes large. The purpose is to provide a heating method.

[0009]

In order to achieve the above object, the method of induction heating of a plate material according to the present invention has a structure in which the plate material is passed through the opening of the substantially C-shaped inductor or is stopped at this opening. In the method of induction heating by applying a magnetic flux penetrating in the plate thickness direction of the plate material between the openings to generate an eddy current in the plate material, when the gap between the plate material and the opening is larger than the minimum gap. In the gap between the plate and the opening, a gap plate made of a material having a small magnetic resistance and a small iron loss is inserted, and a minimum gap is formed between the gap plate and the plate so that the magnetic flux is reduced. And the air magnetic resistance of this gap are reduced.

[0010]

According to the plate material induction heating method of the present invention configured as described above, when the plate material having the plate thickness passing through the opening of the substantially C-shaped inductor less than the maximum allowable value is induction-heated, the gap A gap plate having a thickness corresponding to the increased value is inserted into a portion of the opening facing the plate material, and adjustment is performed so that the gap plate and the plate material form a minimum gap.

Then, when a high frequency current is applied to the inductor to pass both edge portions of the plate material through the substantially C-shaped openings of the inductor and eddy currents penetrate through both edge portions of the plate material in the plate thickness direction, the magnetic flux is filled. It passes through the area where the gap plate exists in a concentrated manner, reduces its spread, and effectively induces and heats only the target portion of the plate material, thus reducing the aeromagnetic resistance of the magnetic flux path.

As a result, the electric power used for induction heating of the plate material can be significantly reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front view showing an example in which an induction heating device is used as an edge heater, which is an embodiment of the present invention, and FIG.
11 is a sectional view taken along line II-II of FIG.

In FIGS. 1 and 2, reference numeral 4 denotes an inductor, which is arranged at both edge portions of the advancing plate member 2, and is provided on the upper surface on both side surfaces in the line direction above the substantially C-shaped openings. A supporting plate 5 having a slanted portion is fixedly installed.

The plate thickness t ₂ of the plate member ₂ is shown in FIG.
This corresponds to the small plate thickness indicated by the chain double-dashed line.

Reference numeral 6 denotes a gap plate having a plate thickness t ₆ in which magnetic resistance is small and iron loss is small, for example, silicon steel plates are laminated, and the plate member 2 and the inductors 4 arranged at both edge portions thereof.
The hook 7 is inserted into a gap between the opening and the substantially C-shaped opening, and has hooks 7 provided with inclined portions that engage with the inclined portions of the support plate 5 on both side surfaces thereof.

Next, the operation of this apparatus will be described. As shown in FIG. 1 and FIG. 2, while each hook 7 is engaged with both support plates 5 from the center side in the plate material width direction, each gap plate 6 is provided with a substantially C-shaped opening of both inductors 4. Each of them is attached to the upper part to form a minimum gap g ₁ with the upper surface of the plate member 2 having a plate thickness t ₂ .

Then, a high-frequency current is applied to the inductor 4 so that both edges of the plate member 2 pass through the substantially C-shaped openings of the inductor member 4, and eddy currents penetrate through both edges of the plate member 2 in the plate thickness direction. Then, the magnetic flux is concentratedly passed through the gap plate 6 to reduce its spread and effectively inductively heat only a desired portion of the plate material 2, thereby forming a minimum gap g ₁ to form a magnetic flux path. Air magnetic resistance is reduced to reduce power loss.

The present invention is not limited to the above-described embodiment, but the joining portion of the hot-rolled plate is stopped at the substantially C-shaped opening of the inductor 4 and the contact portion of the preceding plate material and the following plate material. It can also be applied to the method of joining by induction heating and pressurizing, and all of them belong to the technical scope of the present invention.

[0020]

As described above, according to the induction heating method for a plate member of the present invention, when the gap between the plate member and the inductor opening is larger than the minimum gap, the magnetic resistance is provided in the gap between the plate member and the opening. Magnetic flux is concentrated in the area where the gap plate is present by inserting and filling a gap plate with a material with a small iron loss and a structure with little iron loss, and forming the gap between this gap plate and the plate material to a minimum. Since it can be passed through in a magnetic field, its spread can be prevented, and only the desired part of the plate material can be induction-heated effectively, and the space through which the magnetic flux passes can be shortened, thus reducing the air magnetic resistance of the magnetic flux path. Can be made smaller. Therefore, the electric power used for induction heating of the plate material can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a front view showing an example in which an induction heating device is used as an edge heater, which is an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a front view showing a conventional plate material heating method.

[Explanation of symbols]

1, 2 plate material 4 inductor 6 gap material g ₁ minimum gap g ₂ gap by plate material 2 t ₁ allowable maximum thickness t ₂ plate material 2 thickness t ₆ gap material 6 thickness

Front page continued (72) Inventor Kazunori Nagai 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City Mitsubishi Heavy Industries, Ltd.Hiroshima Plant (72) Inventor Kanji Hayashi 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima Mitsubishi Heavy Industries Ltd. Company Hiroshima Works (72) Inventor Kiyoshi Izumi 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City Mitsubishi Heavy Industries, Ltd. Hiroshima Research Institute (72) Inventor Kazuya Tsurusaki 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima Mitsubishi Heavy Industries Inside the Hiroshima Research Institute (72) Inventor Hideyuki Nikaido 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Kawasaki Steel Co., Ltd. Inside the Chiba Steel Works (72) Takeshi Hirabayashi 1 Kawasaki-cho, Chuo-ku, Chiba Prefecture Kawasaki Steel Inside Chiba Steel Co., Ltd. (72) Hiro right Yamada, 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Inside Kawasaki Steel Co., Ltd. (72) Toshiaki Amagasa, 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Chiba Steel Works, Ltd.

Claims (1)

[Claims] 1. An eddy current is generated in a plate material by passing a plate material through an opening of a substantially C-shaped inductor or stopping at the opening, and applying a magnetic flux penetrating in the plate thickness direction of the plate material between the openings. In the method of induction heating by making the gap between the plate and the opening larger than the minimum gap, the gap between the plate and the opening is a material having a small magnetic resistance and less iron loss. An induction heating method for a plate material, comprising inserting a gap plate having a structure, and forming a minimum gap between the gap plate and the plate material to reduce the spread of magnetic flux and the air magnetic resistance of this gap.