JP2698512B2 - Hearth metal fittings for vertical induction heating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical induction heating apparatus of a lower charging type in which a slab is charged into a furnace from below and is heated at a high temperature and uniformly by induction heating. The present invention relates to a hearth metal fitting to be charged into a furnace.

[0002]

2. Description of the Related Art A vertical induction heating apparatus is used to heat a slab, which has been heated to a predetermined temperature in advance by a continuous heating furnace or the like, at a higher temperature and more uniformly.
For example, Japanese Patent Application Laid-Open No. 62-224630 and Japanese Patent Application Laid-Open
No. 45885 is known.

[0003] In these apparatuses, an induction heating coil is arranged around the outer periphery of a furnace body made of a box-shaped refractory heat insulating material having a slab loading inlet at a lower portion, and is inserted into the furnace body by the induction heating coil. The slab is heated by induction. Then, the slab is loaded into the furnace main body, and the elevating platform and the hearth metal are connected directly to the upper end of a refractory platform made of a block-shaped refractory supported from below by a plurality of support pipes. A plurality of metal hearths made of a heat-resistant metal to be mounted and supported are arranged so as to protrude in a state where they are arranged at predetermined intervals in the furnace length direction. Then, the slab placed on the plurality of hearth hardware is loaded and unloaded into the furnace by raising and lowering the elevating table and the hearth metalware toward the furnace body.

[0004] The hearth metal fitting is disclosed in Japanese Patent Laid-Open No. 4-365.
Conventionally, as described in JP-A-87-87,
Each is integrally formed into one brick shape.

[0005]

When a slab is charged into a furnace and heated, the temperature of the hearth metal on which the slab is mounted also increases, the thermal stress increases, and the heating ends. When the slab and the hearth metal are taken out of the furnace to be in a heat radiation state, the thermal stress applied to the hearth metal sharply decreases. Such a high-temperature low-temperature cycle of thermal stress is applied to the hearth metal every time the slab is heated, and each time the hearth metal undergoes thermal expansion and contraction, the magnitude of the thermal stress and its sudden A predetermined plastic strain according to the change is sequentially accumulated in the hearth metal.

However, in recent years, it has been necessary to heat a slab to a high temperature of 1400 ° C. or more in order to produce directional silicon steel or the like. As the temperature for heating the slab is higher, a furnace for heating the slab is required. Although the thermal stress applied to the floor metal and its rapid change increase, the above-mentioned conventional hearth metal has a large mass per unit because it is integrally formed, so that it is applied to each hearth metal. There is a problem that the thermal stress is large, and thus the high temperature and low cycle fatigue easily causes breakage at an early stage and the life is short.

[0007] In particular, the above-mentioned tendency becomes more remarkable as the heating temperature of the slab is increased. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has an object to provide a hearth metal which is hard to be broken by thermal stress and fatigue caused by a rapid change even when the slab heating temperature is increased.

[0008]

In order to achieve the above object, a furnace hearth in a vertical induction heating apparatus according to the present invention comprises: a furnace body having a lower opening provided with a slab charging opening;
A lift platform that is opposed to the loading port of the furnace body from below and can be raised and lowered toward the loading port, and is arranged in parallel at a predetermined interval in the furnace length direction at the upper end of the lifting platform. In a vertical induction heating apparatus provided with a plurality of hearth hardware capable of mounting a slab on the upper surface, for each of the hearth hardware , the slab and
The upper part, which is in direct contact, is
It is characterized by being formed .

[0009] For example, the upper portion of the hearth hardware in direct contact with the slab, formed by splittable plurality of blocks so as to align in the furnace top or the furnace width direction.

[0010]

[Function] Since each hearth metal is formed of a plurality of divided blocks, the heat stress generated in the hearth metal by heating and cooling at the same temperature as before, and the thermal expansion and contraction due to the thermal stress. Are distributed to a plurality of blocks forming each hearth metal. As described above, since the thermal stress generated in each block and the thermal expansion and contraction deformation due to the thermal stress are small, the life due to high-temperature and low-cycle fatigue until failure is longer than that of the integrally molded hearth metal.

[0011] In particular, the upper part of the hearth metal that comes into contact with the slab is:
Since thermal stress and the change in heat conduction from slabs is largest, the top, effectively acts idea to couple divided into for example a furnace length direction.

[0012]

An embodiment of the present invention will be described with reference to the drawings.
First, the configuration will be described. As shown in FIG. 4, an induction heating coil 2 divided into upper and lower portions is wound around the outer periphery of a box-shaped furnace main body 1 having a slab charging inlet 1a formed below. The induction heating coil 2 is connected to an induction power source 3,
Induction heating can be performed by electric power supplied from the induction power supply 3.

Below the furnace main body 1, an elevator 4 is provided. As shown in FIG. 1, the lift 4 is made of a refractory material, is formed in a block shape extending in the furnace length direction, and its lower part is supported by a plurality of support pipes 5 arranged in the furnace length direction. ing. Each of the support pipes 5 has a water-cooled pipe structure and is lined with a refractory heat insulating material, and can be moved up and down synchronously by an elevating device (not shown).

A plurality of hearth metal fittings 6 are arranged in parallel at a predetermined interval at the upper end of the elevating table 4 along the furnace length direction. Each hearth metal 6 is, as shown in FIGS. 1 to 3, a lower block 7 fixed to the elevator 4,
A total of three upper blocks 8 arranged on the lower block 7 and arranged in the furnace length direction and in direct contact with the slab 9.
Each block is formed in a brick shape.

The lower block 7 has on its lower surface a concave portion 7a which can be engaged with a convex portion 4a formed on the upper portion of the lifting platform 4, and engages the concave portion 7a with the convex portion 4a of the lifting platform 4. At the same time, it is fixed to the lift 4 by two pins 10 penetrating in the furnace width direction. Two projections 7b extending in the furnace width direction are formed on the upper surface of the lower block 7, and locking grooves 7c and locking notches 7d are formed on both left and right sides of each of the projections 7b. I have.

A groove 8a extending in the furnace width direction is formed at the center of the lower surface of each upper block 8, and the right and left feet 8b of the groove 8a are relatively engaged with the locking grooves 7c of the lower block 7. The foot 8b is formed so as to be engageable with the locking notch 7d, and its foot 8b is locked to the locking groove 7c of the lower block 7.
The two upper blocks 8 are fixed on the lower block 7 side by side in the furnace length direction by pins 11 penetrating in the furnace width direction while being engaged with the locking notches 7d, respectively.

A slab 9 having a width in the vertical direction is placed on the plurality of hearth metal members 6 configured as described above, and the support pipe 5 and the lifting table 4 are moved by the operation of a lifting device (not shown). The metal hearth 6 and the slab 9 are inserted and heated through the furnace. When the heating of the slab 9 is completed, the metal hearth 6 and the slab 9 are taken out of the furnace and the metal hearth 6 is allowed to cool. .

Further, a new slab 9 is placed on the hearth metal fitting 6, and the above processing is repeated. In this manner, heating and cooling are repeatedly performed on the hearth metal piece 6, and expansion and contraction are applied due to a change in thermal stress at that time. However, the heat generated in each hearth metal piece 6 itself is increased. Even though the amount of expansion and contraction is the same as in the prior art, in this embodiment, since each hearth metal 6 is formed by three blocks,
Thermal stress and its deformation are distributed to each block 7 and 8,
The thermal stress of each block unit and its thermal expansion and contraction deformation become smaller, and are generated by the fatigue caused by the above high temperature and low cycle.
The life until the hearth metal 6 is broken is longer than before.

In the above embodiment, the two upper blocks 8 are arranged side by side in the furnace length direction. However, they may be arranged in the furnace width direction so as to be splittable. The joining surface between the eights does not need to be flat, and may be any other known shape as long as they can engage with each other. Further, each hearth metal member 6 may be formed by being divided into four or more blocks.

Further, in the above embodiment, each block 6,
Although the pins 7 are fixed by pins, the present invention is not limited to the pin connection, and the blocks may be fixed by other known connection means such as a key connection. Further, in the above-described embodiment, the lift 4 is formed as an integral body. However, as shown in FIG. 5, the lift 4 may be divided into individual hearth metal fittings 6 or support pipes 5 to be in a separated state. .

[0021]

As described above, the hearth metal in the vertical induction heating apparatus of the present invention has the effect that the life of the hearth metal with respect to the thermal stress due to repeated heating and cooling is longer than in the past. Is obtained.

[Brief description of the drawings]

FIG. 1 is a side view showing a hearth metal fitting and a lifting platform in a vertical induction heating apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a perspective view showing a hearth metal according to an embodiment of the present invention.

FIG. 4 is a schematic configuration diagram showing a vertical induction heating apparatus according to an embodiment of the present invention.

FIG. 5 is a side view showing a hearth metal fitting and an elevator in a vertical induction heating apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

 4 Lifting table 6 Hearth metal 7 Lower block 8 Upper block 9 Slab

Claims (1)

(57) [Claims] 1. A furnace body having a lower opening provided with a slab loading opening, a lifting platform opposed to the loading opening of the furnace main body from below, and capable of moving up and down toward the loading opening. A vertical induction heating apparatus comprising: a plurality of hearth metal members which are arranged in parallel at predetermined intervals in the furnace length direction at an upper end of a table and on which a slab can be placed; on the floor hardware
The upper part that comes in direct contact with the slab
A metal hearth in a vertical induction heating device, wherein the metal hearth is formed by the following block .