JPH11251049A - Induction heating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an induction heating apparatus in which a crack is prevented from being produced by cooling a fire resistive material layer by water, insulation of a solenoid coil is prevented from being deteriorated by blocking intrusion of oxide scale and heating efficiency is enhanced by forming the thin fire resistive material layer. SOLUTION: In this induction heating apparatus, a fire resistive material layer 4 is provided inside a solenoid coil 2 extending laterally in the sheet width direction of a heated sheet material 1 carried on a hot rolling line for iron and steel, and induction heating is applied to the heated sheet material 1 by forming a cylindrical heating passage 5 there. The fire resistive material layer 4 is structured cylindrically by combining plural flat blocks 4a formed of castable cement 3 and curved corner blocks 4b, and a stainless steel pipe 11 a for cooling water passage is embedded inside those blocks 4a, 4b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating apparatus for heating a sheet-like material to be conveyed on a hot rolling line for steel in the middle of the line.

[0002]

2. Description of the Related Art Generally, in a hot rolling line for steel, a plate-shaped material to be heated (slab) heated in advance to a high temperature in a heating furnace is continuously passed through a rolling mill to be processed into a thin plate. I have. When a thin plate is rolled in such a steel hot rolling line, the distance from the heating furnace to the rolling mill is long, so that there is a problem that the temperature drops before reaching the rolling mill. For this reason, the plate-like material to be heated is heated in the middle of the line to once raise the entire temperature, and then both ends are locally heated by an edge heater to make the whole substantially uniform temperature state and passed through a rolling mill. Rolled into thin plates.

[0003] As described above, an induction heating apparatus for heating the entire plate-like material to be heated in the middle of the line to increase the temperature is shown in FIG.
As shown in FIG. 1, a water-cooled copper tube is wound to form a solenoid coil 2 which is elongated in the width direction of the plate-like material 1 to be heated, and a refractory material layer 4 made of castable cement 3 is provided inside the solenoid coil 2. Here, a cylindrical heating passage 5 is formed, and the plate-shaped material to be heated 1 is passed through the heating passage 5 to perform induction heating on the whole.

In this case, the solenoid coil 2 is protected by various insulating materials for electrical insulation.
This insulating material has a heat resistance temperature of about 180 ° C., and the radiant heat from the induction-heated plate-shaped material to be heated 1 is as high as 1000 to 1100 ° C. Therefore, to protect the coil insulating material, A refractory layer 4 is provided. In addition, conductive oxide scale is generated on the surface of the plate-like material 1 heated to a high temperature. If the oxide scale falls off and is attracted by a magnetic force, the insulation of the coil is deteriorated. Also prevents intrusion.

Further, a plate-like material to be heated 1 and a solenoid coil 2
The smaller the gap is, the better the heating efficiency is. However, the conventional induction heating apparatus has a problem in that the heating efficiency is reduced because the refractory material layer 4 is formed thicker from the viewpoint of heat insulation and prevention of oxide scale intrusion. Was. The refractory material layer 4 is a plate-like material 1 to be heated.
The outer side of the tubular refractory material layer 4 is formed in a tubular shape that is horizontally elongated in the plate width direction.
, Cracks 6 are easily formed due to thermal stress due to high-temperature radiant heat. When the cracks 6 are thus formed, there is a risk that the refractory material may fall off, or the oxide scale may enter the inside from the dropped-off portion, resulting in deterioration of insulation of the coil.

[0006]

SUMMARY OF THE INVENTION The present invention eliminates the above-mentioned disadvantages and prevents the occurrence of cracks by water-cooling the refractory material layer, and prevents the deterioration of the solenoid coil by preventing the penetration of oxide scale. In addition, an object of the present invention is to provide an induction heating device in which the heating efficiency is improved by forming a thin refractory material layer.

[0007]

According to a first aspect of the present invention, there is provided an induction heating apparatus comprising: an inner side of a solenoid coil which is elongated in a sheet width direction of a plate-like material to be heated conveyed on a hot rolling line for steel. A refractory material layer is provided in the induction heating device for forming a cylindrical heating passage here and inductively heating the plate-shaped material to be heated, wherein the refractory material layer is formed of a plurality of flat blocks formed of castable cement. It is characterized in that it is formed into a cylindrical shape by combining with curved corner blocks, and a stainless steel pipe serving as a water passage for cooling water is embedded inside these blocks.

In the induction heating apparatus according to the second aspect, stainless steel pipes are buried inside each block constituting the tubular refractory material layer to form independent water passages.
The outer periphery of each block is surrounded by an insulating support plate, and the block is connected to and held by a stainless steel tube.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is shown in FIG.
This will be described in detail with reference to FIG. As shown in FIG. 1, this induction heating device winds a water-cooled copper tube 7 to form a solenoid coil 2 that is horizontally elongated in the plate width direction of a plate-like material 1 to be heated.
Are formed. A refractory material layer 4 having an insulating support plate 8 attached to the inside of the solenoid coil 2 is provided, and a cylindrical heating passage 5 is formed therein. Is induction-heated.

The refractory material layer 4 is formed in a tubular shape by combining a plurality of flat blocks 4a formed of castable cement 3 and L-shaped corner blocks 4b. As shown in FIGS. 2 and 4, the flat blocks 4a are stainless steel pipes serving as cooling water passages 10.
11 is spirally wound, around which the castable cement 3 is poured and integrally molded. Also L
As shown in FIG. 3, the curved corner blocks 4b are formed by forming a stainless steel pipe 11 serving as a cooling water passage 10 in a meandering manner, casting castable cement 3 around the pipe, and integrally forming the same. is there. The stainless steel tube 11 used has a wall thickness smaller than the current penetration depth.

In order to hold the spirally or meandering stainless steel pipe 11, studs 12 are provided at predetermined intervals on the stainless steel pipe 11 as shown in FIG. The stud 12 is penetrated through an insulating support plate 8 formed of a glass laminate or the like, and is fixed and held by a stainless steel nut 14. As shown in FIG. 1, the L-shaped curved corner blocks 4b and 4b constituting the left and right inner wall sides of the cylindrical heating passage 5 are as follows.
It is mounted so that the outside thereof is integrally surrounded by a U-shaped insulating support plate 8.

Further, as shown in FIG.
, And stepped portions 16 are provided on both side end surfaces of the corner blocks 4b curved into an L shape, and the adjacent blocks 4a, 4b
The gap is filled with a mortar 17 as shown in FIG.

In the induction heating apparatus having the above-described structure, a high frequency current is applied to the solenoid coil 2 by passing the traveling plate-like material 1 through a cylindrical heating passage 5 so that the plate-like material to be heated is continuously provided. The whole of 1 is induction-heated. In this case, when cooling water is passed through a stainless steel pipe 11 buried inside the refractory material layer 4 facing the plate-shaped material to be heated 1, the refractory material layer 4 is cooled from the inside and the plate heated to about 1100 ° C. The temperature rise can be suppressed to a low level even when the material is heated by radiant heat from the material 1 to be heated.

A mortar 17 is filled between the flat portions 4a of the refractory material layer 4 and the stepped portions 16 of the L-shaped corner blocks 4b. As a result, intrusion of radiant heat from here can be prevented. The refractory material layer 4 is composed of blocks 4a, 4b,.
, The thermal stress is absorbed by the fitting portion of the step portion 16 and the occurrence of cracks can be prevented. Moreover, since the outer sides of the L-shaped curved corner blocks 4b and 4b constituting the left and right inner wall sides of the heating passage 5 are mounted so as to be integrally surrounded by a U-shaped insulating support plate 8,
The occurrence of cracks at corners can be prevented.

Further, since the stainless steel pipe 11 serving as the water passage 10 is made of a non-magnetic material and has a thickness smaller than the current penetration depth, the temperature rise is low even when heated by magnetic flux.
The temperature on the coil side can be suppressed to about 100 ℃. As a result, it is possible to prevent the thermal deterioration and cracks of the refractory material layer 4 from being generated, maintain the hardness and strength, and prevent the penetration of the oxide scale and the insulation deterioration of the solenoid coil 2 for a long time.

FIG. 5 shows another embodiment of the present invention, in which a stainless steel pipe 11 is spirally or meanderingly piped.
Studs 12 are projected from the stainless steel tube 11 at predetermined intervals, and the studs 12 are passed through an insulating support plate 8 provided on the solenoid coil 2 side and formed of a glass laminated plate or the like. And studs 12 are not provided with glass fiber 18
To hold the whole.

Further, a convex portion 19 and a concave portion 20 are formed on both side end surfaces of the flat block 4a... And the L-shaped curved corner block 4b that constitute the refractory material layer 4, and the convex portions of the adjacent blocks 4a and 4b. 19 and the recess 20 are fitted together, the gap is filled with mortar 17, and joined together. The fitting structure of the adjacent blocks 4a and 4b is not limited to the above-described configuration, and may be a combination of inclined surfaces or another combination such as a combination of a concave curved portion and a convex curved portion.

[0018]

As described above, according to the induction heating apparatus of the present invention, a cylindrical refractory material layer is formed by combining a plurality of flat blocks and curved corner blocks, and is formed in this block. A cooling pipe made of stainless steel pipe made of non-magnetic material is piped to cool from the inside, so heating by radiant heat from the plate-like heated material is kept low and the life of the refractory material layer is greatly extended. In addition, it is possible to prevent the dielectric breakdown and short circuit of the solenoid coil for a long period of time, and to perform a stable operation. In addition, the tubular refractory material layer is formed by combining a plurality of blocks, so that molding is easy, and when a part is damaged, only the damaged block can be replaced, so repair work is also easy. is there.

According to a second aspect of the present invention, there is provided an induction heating apparatus, wherein a stainless steel pipe made of a non-magnetic material is embedded in each of the blocks constituting the tubular refractory material layer to form independent water passages, Surround the outer periphery with an insulating support plate,
Since the stainless steel tube is connected and held, the temperature rise is low even if the stainless steel tube is heated by magnetic flux, and since the stainless steel tube is securely held by the insulating support plate surrounding the outside, the refractory material It is possible to prevent falling and to prevent the occurrence of cracks at corners.

[Brief description of the drawings]

FIG. 1 is a sectional view of an induction heating device according to an embodiment of the present invention.

FIG. 2 is a plan view showing the flat block shown in FIG. 1;

FIG. 3 is a perspective view showing an L-shaped curved corner block shown in FIG. 1;

FIG. 4 is an enlarged sectional view showing the flat block shown in FIG. 1;

FIG. 5 is an enlarged sectional view showing a flat block according to another embodiment of the present invention.

FIG. 6 is a sectional view showing a conventional induction heating device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plate-shaped heated material 2 Solenoid coil 3 Castable cement 4 Refractory layer 4a Flat block 4b Corner block 5 Cylindrical heating passage 7 Water-cooled copper tube 8 Insulation support plate 10 Water passage 11 Stainless steel tube 12 Stud 16 step 18 Glass fiber

Claims (2)

[Claims] 1. A refractory material layer is provided inside a solenoid coil which is elongated in the width direction of a plate-shaped material to be heated conveyed in a steel hot rolling line, and a cylindrical heating passage is formed therein. In the induction heating apparatus for induction heating the plate-shaped material to be heated, the refractory material layer is formed into a tubular shape by combining a plurality of flat blocks formed of castable cement and curved corner blocks, and An induction heating device characterized by burying a stainless steel pipe as a cooling water passage inside. 2. A stainless steel pipe is buried inside each block constituting a cylindrical refractory material layer to form an independent water passage, and the outer periphery of each block is surrounded by an insulating support plate. The induction heating device according to claim 1, wherein the tubes are connected and held.