JPH0730390B2 - Vertical induction heating device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vertical induction heating apparatus that heats a steel material to a temperature at which it can be rolled without oxidation in a step of hot rolling the steel material. In other words, the purpose thereof is to prevent a decrease in heating efficiency due to the atmospheric gas supplied into the induction heating device.

[Conventional technology]

FIG. 6 shows the basic configuration of a vertical induction heating device. In FIG. 6, reference numeral 1 denotes a furnace body in which a heating coil 2 is assembled, and a support metal member 3 on which a heating steel material K is directly mounted and a support member 4 on which the support metal member 3 is mounted and fixed to the furnace member 1. Assemble the combination with and move up and down, heated steel material K
The combination of the support hardware 3 and the support body 4 is raised with respect to the furnace body 1 in a state in which the heating steel material K is placed on the support metal body 3 so that the heating steel material K is inserted into the furnace body 1 and the furnace body The inside of the furnace body 1 is sealed from the outside air by a sealing device 13 provided between the lower end of the furnace 1 and the support body 4.

In this vertical induction heating device, when the heated steel material K is heated to a high temperature of 1300 ° C. or higher, the generated scale melts and damages the structure of the furnace body 1, or when the heated steel material K after heating is rolled. In addition, there is a great adverse effect such as deterioration of product surface properties due to molten scale and damage of rolling rolls.
Gazette, Japanese Utility Model Publication No. 48-113741, Japanese Utility Model Publication No. 48-09
As disclosed in Japanese Patent No. 1555 etc., a method has been proposed in which a furnace body 1 is filled with a non-oxidizing atmosphere gas G such as nitrogen gas and the heated steel material K is heated to a high temperature in the non-oxidizing atmosphere. There is.

In the above-mentioned conventional example, the atmosphere gas G is supplied into the furnace body 1 by forming an atmosphere gas supply port 14 at the upper part or the lower part of the furnace body 1 as shown in FIG. The atmosphere gas G was forcibly fed from the supply port 14 to achieve the supply of the atmosphere gas G into the furnace body 1.

The heating of the heated steel material K while supplying the atmosphere gas G into the furnace body 1 can heat the heated steel material K in the non-oxidizing atmosphere, whereby almost the molten scale is generated in the heated steel material K during heating. It has the advantage of not allowing it.

Further, since the heated steel material K is heated to a high temperature while being placed and supported on the support hardware 3, the support hardware 3 is also heated to a temperature close to the heated steel material K by heat transfer from the heated steel material K heated to a high temperature. Therefore, a heat-resistant alloy is used as the support hardware 3.

However, even with CO alloys that have high temperature and high strength at present, the heat resistance limit temperature is about 1300 ° C, and ceramics are considered as long as they can withstand only the temperature. There are unsolved problems such as cracking due to thermal shock due to its unique rapid heating, and the practical use of this ceramic is far from achieved. Therefore, in practice, it is necessary to cool the support hardware 3 that is being driven.

An example of cooling means for the support hardware 3 is shown in FIG. In FIG. 7, a support body 4 for mounting and supporting the support hardware 3 is configured by supporting pipe 5 and an outer surface of the support pipe 5 covered with a heat insulating material 6, and a conduit 9 is provided from a bottom wall of the support pipe 5 to an upper end. By assembling up to the vicinity of the portion and forming a drainage port 11 at the lower end of the support pipe 5, the inside of the support pipe 5 serves as a cooling water passage space 12 to form a cooling function portion of the support hardware 3. The cooling water W from the outside is supplied from the inlet 10 which is the lower end opening of the conduit 9 and passes through the conduit 9 to the upper part of the support pipe 5 and opens toward the support metal 3
Is ejected toward the lower surface of the support hardware 3 from the upper end opening of the. The cooling water W jetted to the lower surface of the support hardware 3 comes into contact with the support metal part 3 to cool the support metal 3,
Next, while cooling the support pipe 5, the cooling water passage space 12 between the support pipe 5 and the conduit 9 flows down and the discharge port
Emitted from 11.

By cooling the support hardware 3 in this way, it is prevented that the support hardware 3 is heated more than necessary and deteriorates.

[Problems to be solved by the invention]

In this way, by feeding the non-oxidizing atmosphere gas G into the furnace body 1, generation of molten scale is suppressed, the occurrence of the above-mentioned inconvenience is prevented, and by cooling the support metal 3, the support metal 3 is cooled. Although it is possible to prevent the deterioration due to heating of No. 3, the conventional atmospheric gas G is fed into the furnace body 1 through the atmospheric gas supply port 14 formed in the upper or lower part of the furnace body 1. Since the gas is supplied directly into the furnace body 1, the atmosphere gas G having a temperature much lower than that in the high temperature furnace body 1 is directly fed into the furnace body 1. Due to G, the inside of the furnace body 1 tends to be cooled, and as a result, the thermal efficiency of the furnace is significantly reduced. Further, since the installation location of the atmosphere gas supply port 14 is specified, the atmosphere gas G supplied to the inside of the furnace body 1 is locally supplied, which causes the heated steel material K to be locally supplied. However, there is a problem in that the heating of the heated steel material K is non-uniform.

Further, since the cooling of the support hardware 3 by the cooling water W through the support body 4 is simply performed by removing the heat of the support hardware 3 by the cooling water W, the furnace efficiency in the heating device, that is, the heating efficiency of the heating steel material K. Cause to decrease.

The problem in the above-mentioned conventional example is that the atmosphere gas G is supplied into the furnace body 1 without preheating, and the cooling of the support hardware 3 by the cooling water W is achieved only by heat removal. This is because there was no technical idea to combine thermally contradictory matters such as preheating for the atmospheric gas G and cooling for the support metal 3 so as to be organically effective.

Therefore, in the present invention, the ambient gas G supplied into the furnace body 1 is used.
To preheat and the support metal 3 are thermally and organically combined to supply the atmosphere gas G into the furnace body 1.
It is a technical subject to integrally achieve the preheating for and the cooling for the support hardware 3.

[Means for solving problems]

Hereinafter, the present invention will be described with reference to the drawings showing an embodiment of the present invention.

The means of the present invention relates to the structure of a vertical induction heating device that induction-heats a heated steel material K, a support hardware 3 on which the heated steel material K is directly placed, and a support body 4 on which the support hardware 3 is mounted and supported. And (see FIG. 1), the support body 4 has a passage space 8 (see FIG. 2) as a supply passage for the atmospheric gas G fed into and fed into the furnace body 1 which is the main body of the induction heating device. Is provided, and the passage 3b communicates with the passage space 8 in the support hardware 3 and also communicates with the plurality of ejection openings 3a formed in the side surface of the support hardware 3.
(See FIG. 2).

Since the plurality of ejection holes 3a are formed in the side surface of the support metal 3, the combination of the support metal 3 and the support 4 is moved up relative to the furnace body 1 to heat the induction heating device. In the operable state, each of the ejection ports 3a opens opposite to the lower end of the inner surface of the cylindrical wall of the furnace body 1 (see FIG. 1).

[Action]

The atmosphere gas G sent and supplied into the furnace body 1 in which the combination of the support hardware 3 and the support body 4 is assembled is supplied to the passage space 8 in the support body 4 and then the support metal 3
Since it is ejected from the ejection port 3a into the furnace body 1 through the passage 3b formed in the inside, when it passes through the passage space 8 and the passage 3b, it is heated by the support body 4 and the support metal piece 3 in a heated state. Will be done. In particular, when passing through the passage 3b, it is heated to a considerable temperature by the support hardware 3 which is in a state of being heated to a high temperature. That is, the atmospheric gas G that is supplied into the furnace body 1 through the passage space 8 and the passage 3b is jetted and supplied into the furnace body 1 while being sufficiently preheated by the support body 4 and the support hardware 3. It becomes.

Further, the fact that the atmosphere gas G is heated by the support hardware 3 when passing through the passage 3b means that the atmosphere gas G passing through the passage 3b takes heat from the support hardware 3, that is, the support hardware 3 is cooled. Will be done.

In short, by supplying the atmosphere gas G to be supplied into the furnace body 1 into the furnace body 1 through the support hardware 3,
The atmosphere gas G takes heat from the support metal fitting 3 having a high temperature to cool the support metal fitting 3, and the atmosphere gas G that takes heat from the support metal fitting 3 and cools the support metal fitting 3 supports By removing the heat from the metal 3, it is supplied into the furnace body 1 in a sufficiently preheated state.

Thus, if the relationship between the atmospheric gas G supplied into the furnace body 1 and the support hardware 3 is from the support hardware 3 side,
This is preheating of the atmospheric gas G, and from the side of the atmospheric gas G, by cooling the support hardware 3, the amount of heat given to the induction heating device is not newly added and lost, G can be supplied into the furnace body 1 in a sufficiently preheated state, and cooling of the support hardware 3 can be achieved. By preheating this atmosphere gas G and supplying it into the furnace body 1, the heating rate of the heated steel material K when the atmosphere gas G is preheated is higher than the heating rate of the heating steel material K when the atmosphere gas G is not preheated. Much larger,
Therefore, when the same heating power is supplied to the induction heating device, the same heating steel material K is heated to the target temperature, but the heating time can be greatly shortened, and faster rapid heating by induction heating can be achieved.

〔Example〕

FIG. 2 shows a concrete structure example of a combination of the support hardware 3 and the support body 4 in FIG. 1 showing a basic embodiment of the present invention. 8 and a heat insulating material 6 assembled so as to cover the outer surface of the support pipe 5, and a supply port 7 for the atmospheric gas G is opened at the lower end of the support pipe 5. Has been formed.

As shown in FIG. 4, a large number of jet holes 3a are provided on both side surfaces of the support metal fitting 3 mounted on the support body 4 at substantially regular intervals over the entire front-back width range of the support metal fitting 3. The passages 3b, which are arranged and communicate with the large number of ejection ports 3a, open to the lower surface of the support hardware 3 and communicate with the passage space 8.

In this way, since a large number of ejection ports 3a are arranged and formed over the entire front and rear width range of the support hardware 3, this ejection port 3a is formed.
The atmosphere gas G vigorously ejected from the inner surface 3a of the furnace 1 forms a kind of gas curtain,
Even if air from the outside is easily infiltrated despite the sealing action of the sealing device 13, the gas curtain is formed due to the pressure in the lower part of the inside being lowered by the draft of the heated internal atmosphere. By the atmosphere gas G to be generated, it is possible to effectively prevent the invasion of the external air into the substantially heated portion of the heated steel material K in the furnace body 1.

When the cooling of the support hardware 3 by the atmosphere gas G is insufficient, as shown in FIG. 3, the cooling water passage space 12 of the cooling function structure by the conventional cooling water W shown in FIG. The passage spaces 8 are alternately arranged adjacent to each other along the front-rear direction of the support body 4, so that the cooling power of the cooling function structure by the cooling water W compensates for the insufficient cooling of the support hardware 3 and the passage space 8 is formed. It is preferable to cool the passing atmosphere gas G to enhance the cooling effect of the atmosphere gas G on the support hardware 3. In this case, that is, when the conventional cooling means is used together with the cooling by the atmospheric gas G for cooling the support hardware 3, the cooling power by the conventional cooling means is the cooling power by the atmospheric gas G for the support metal 3. To the extent that it compensates for the shortage, and so pay attention not to make the cooling effect on the support hardware 3 excessive, and try to minimize the decrease in the heating efficiency of the induction heating device by this conventional cooling means. There is a need.

Furthermore, by preheating the atmospheric gas G and supplying it into the furnace body 1, specifically, as shown in FIG. 5, a heating characteristic curve showing the heating rate of the heated steel material K when the atmospheric gas G is not preheated. From the size of the inclination angle of the heating characteristic curve (b) that shows the heating rate of the heated steel material K when the atmospheric gas G is preheated with respect to the inclination angle of (a) When the steel material K is heated to the target temperature T of 1350 ° C., the heating time of the vertical induction heating device can be shortened by ΔΘ, that is, 4 minutes, when the atmospheric gas G is preheated. It was possible to obtain the effect of shortening about 10%.

〔The invention's effect〕

As is clear from the above description, the present invention can prevent the cooling of the inside of the furnace body by the atmospheric gas supplied to the furnace body and achieve the cooling of the support metal without removing the heat, so that the heating efficiency in the induction heating device can be improved. Since the heated steel is not cooled by the atmospheric gas, the uneven heating of the heated steel can be reliably prevented, and the uniform heating time to the target temperature of the heated steel can be shortened. As a result, the operation time of the induction heating device can be shortened and the power consumption can be significantly reduced. Furthermore, it is easy to form a passage for supplying atmospheric gas into the furnace inside the support hardware. Since it has such a configuration, it exhibits many excellent effects such that it can be easily implemented regardless of existing or new installation.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing a basic configuration example of an embodiment according to the present invention. FIG. 2 is a vertical sectional front view showing the structure of the combination of the support hardware and the support body in the embodiment shown in FIG. FIG. 3 is a vertical sectional side view taken along the line AA in FIG. FIG. 4 is a partially cutaway perspective view of the embodiment shown in FIG. FIG. 5 is a heating characteristic diagram showing a comparison of the characteristics of the conventional apparatus and the apparatus of the present invention in the heating rate characteristic for the heated steel material. FIG. 6 is a vertical sectional front view showing a typical configuration of a conventional induction heating device. FIG. 7 is a vertical sectional front view showing a conventional cooling means for the support hardware. DESCRIPTION OF SYMBOLS 1; furnace body, 2; heating coil, 3; support hardware, 3a; spout, 3
b; passage, 4; support body, 5; support pipe, 6; heat insulating material,
7; Supply port, 8; Passage space, 9; Conduit, 10; Inlet port, 11; Drainage port, 12; Cooling water passage space, 13; Sealing device, 14; Atmospheric gas supply port, K; Heating steel material, G; Atmospheric gas, W; cooling water.

Claims (2)

[Claims] 1. A vertical induction heating apparatus for induction heating a heated steel material (K), and a support hardware (3) for directly mounting the heated steel material (K) and a support for mounting and supporting the support hardware (3). A support body (4) having a body (4)
Gas (G) supplied into the induction heating device
A plurality of spouts formed in the side surface of the support hardware (3) while communicating with the passage space (8) in the support hardware (3). A vertical induction heating device formed by forming a passage (3b) communicating with (3a). 2. A support body (4) for the passage space (8).
Claim 1 wherein the cooling water passage space (12) formed in the support body (4) is positioned adjacent to the cooling water passage space (12) to cool the cooling water.
Vertical induction heating device described in paragraph.