JPS6324584A - Inductor and apparatus for heating edge of metallurgy product by electromagnetic induction - Google Patents

Abstract

The inductor consists of an ''E'' - shaped yoke (4) with wound poles, having two end poles (6, 7) aligned with a first axis (13) and facing one another, thus defining between them a free no-load air-gap for the passage of one edge of the product, and a central pole (5) pointing along a second axis (14) perpendicular to the first axis (13) and set back relative to the end poles so as not to overlap the said air-gap, the windings (8, 9, 10) of these poles being configured so that, whilst operating, the sum of both the fluxes entering or leaving through the end poles (6, 7) is equal to the flux leaving or entering through the central pole (5). <IMAGE>

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the electromagnetic induction reheating of the ends of metallurgical products.

In a rolling mill directly connected to a continuous casting machine, it is desirable to reheat the ends of the slab to obtain a product with a uniform temperature across the rows of rolling rolls. In fact, the heat deficit, ie the difference in average temperature between the center and the edges within the thickness of the slab, amounts to about 120° C. at the exit of continuous casting. This is because the cooling means preferentially cools the ends.

To eliminate edge inhomogeneities in metallurgical products, reheating by electromagnetic induction has already been proposed. This reheating is limited to the ends and uses inductors with U-shaped magnetic yokes placed above and below the product. The metallurgical product moves horizontally in an air gap provided between two inductors that are magnetized with opposite polarity.

Furthermore, the inventor has disclosed that French patent application No. 85086
No. 84 (June 7, 1985), we have already proposed improvements to the above device. According to this, a C-shaped inductor is used that sandwiches the product from the sides.

However, this inductor is particularly suitable for reheating relatively thin products (eg 30-50 mm thick).

Reheating the edges of thicker products (for example, 250 mIn thick) is insufficient with known inductors, and there is a risk that the core will not be heated.

It is an object of the present invention to provide a new type of inductor for reheating the ends of thick metallurgical products, such as continuously cast slabs, which has a higher performance than known inductors.

The inductor according to the invention is constituted by an E-shaped yoke with coiled magnetic poles, the yoke having end poles aligned on a first axis and facing each other, the end poles having: The yoke defines an air gap between which the end of the metallurgical product passes;
a central magnetic pole disposed in a direction along a second axis perpendicular to the first axis, the central magnetic pole relative to the two end magnetic poles so as not to intrude into the air gap; each of the three poles is provided with a coil such that in operation, the sum of the two magnetic fluxes entering or exiting the end poles is equal to the flux exiting or entering the center pole. It is characterized by being made equal.

Such a configuration allows the air gap to be reduced to a minimum. The air gap corresponds to the distance that the magnetic field would span outside the yoke if it were to follow the preferred path determined by the yoke. This arrangement also allows more magnetic flux to be concentrated on the product.

In the reheating device according to the invention, a plurality of the above-described inductors are installed such that the path of the end crosses the air gap of the inductors. However, the end magnetic poles are oriented in the direction of the thickness of the product.

Other features and advantages will become more apparent from the following description of preferred embodiments. The following invention will be made with reference to the accompanying drawings.

In FIG. 1, the end 1 of the slab 2, moving in a direction perpendicular to the plane in which the drawing is drawn, passes through the air gap of the inductor 3.

The inductor comprises a magnetic yoke 4, which is in the shape of a capital letter E. That is, three magnetic poles 5.6.
7 towards the end 1 of the slab, and each coil 8 .
9.10. The central magnetic pole 5 faces in the direction of the width of the slab 20 (axis 13), while the end magnetic poles 6.7 face in the direction of the thickness of the slab (axis 14) and are spaced apart, In between, an air gap is defined with no product to be heated. Through this air gap passes the end of the product to be heated. Therefore, when the central magnetic pole 5 is provided on the yoke, it is located at a position recessed relative to the end magnetic poles 6.7 so as not to enter the air gap.

Coils 8.9.10 are connected as shown in FIG. The amount of current flowing through the central coil 8 is therefore equal to the sum of the amounts of current flowing through the coils 9, 10 of the opposing magnetic poles.

The amount of current flowing through the coils 9.10 is in principle equal. Under these conditions, if the coils have the same number of turns and the direction of each turn is appropriate, the flux towards the central pole 5 is equal to the sum of the fluxes leaving the poles 6.7. The magnetic field lines also pass through the ends of the slab, as shown by arrows 11. Therefore, the desired area is reheated. The frequency of the inductor power supply is approximately 300 Hz.

Although the inductor 3 is not shown, it is installed in a frame that moves the inductor horizontally (in the direction of arrow 12 or in the opposite direction), thereby making it possible to change the position of the inductor according to the width of the product. can.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an electromagnetic induction reheating device for the edge of a slab end, showing two E-type inductors according to the invention. FIG. 2 shows the branching of the coil of an inductor according to the invention. (Main reference numbers) 1. End, 2. Metallurgical product, 3. Inductor, 4. Yoke, 5.6.7. Magnetic pole, 8.9.10. Coil, 13. No. 2 axis, 14・
・First agent Patent attorney Masahiko Arai Procedural amendment (voluntary) March 31, 1985 3. Relationship with the case of the person making the amendment Patent applicant 4. Agent

Claims (3)

[Claims] (1) constituted by an E-shaped yoke (4) with coiled magnetic poles, the yoke having end magnetic poles (6, 7) aligned on a first axis (14) and facing each other; the end poles (6, 7) define an air gap between which the end of the metallurgical product passes;
The yoke has a second axis (13) perpendicular to the first axis.
a central magnetic pole (5) arranged in a direction along said central magnetic pole (5), said central magnetic pole being positioned downwardly relative to said two end magnetic poles so as not to penetrate said said air gap; Each of the three magnetic poles has a coil (8, 9, 10
), and during operation, the above end magnetic poles (6, 7
) by electromagnetic induction in the end (1) of the metallurgical product (2), characterized in that the sum of the two magnetic fluxes entering or exiting the central pole (5) is equal to the magnetic flux exiting or entering the central pole (5). Inductor for reheating. (2) constituted by an E-shaped yoke (4) with coiled magnetic poles, the yoke having end magnetic poles (6, 7) aligned on the first axis (14) and opposite to each other; and the end poles (6, 7) define an air gap therebetween, and the yoke is arranged in a direction along a second axis (13) perpendicular to the first axis. central magnetic pole (
5), the central magnetic pole is positioned downwardly relative to the two end magnetic poles so as not to intrude into the air gap, and each of the three magnetic poles is equipped with a coil (8, 9). , 10) are provided such that, in operation, the sum of the two magnetic fluxes entering or exiting said end poles (6, 7) is equal to the magnetic flux exiting or entering said central pole (5). An end portion (1) of a mobile metallurgical product (2) comprising a plurality of inductors, the inductors being arranged such that a path through which the end portion of the metallurgical product passes crosses an air gap of the inductors. Reheating device using electromagnetic induction. 3. Device according to claim 2, characterized in that the inductor (3) is mounted on a support member that moves perpendicularly to the direction of movement of the metallurgical product.