JPH08303965A - Crucible type induction furnace for melting low melting point metal plated steel plate - Google Patents

Abstract

PURPOSE: To prevent occurrence of hot molten metal leakage alarm caused by erroneous operation or occurrence of accident of short-circuit of a coil or the like by a method wherein zinc vapor seal material having a stainless steel plate and a plate of insulating material are overlapped and wound is applied at an inner cicumference of furnace coil cement. CONSTITUTION: A metal seal plate of a thickness of 1.0mm made of non- magnetic austenite stainless steel of high melting point and an insulation plate are overlapped between a thermal insulating material 3 inside induction heating coil 6 of an induction melting crucible furnace 10 and a coil cement 5 so as to form a laminated plate 11. This plate is wound by more than one turn to form a wrap part and then a zinc vapor shielding seal is constructed. The insulating plate is placed at a portion where the metallic seal plates are overlapped to each other to prevent short-circuit, so that even if zinc vapor reaches up to a layer of the thermal insulating material, the vapor is completely prevented from being reached outside of it. In addition, it is also prevented for the metallic seal plates from being short-circuited to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to melting in a induction melting crucible furnace for remelting scraps of low melting point metals, steel plates plated with low melting point metals, typically galvanized steel plates, and reusing as iron resources. The generated zinc vapor adheres to and accumulates on each member that constitutes the side wall of the furnace, and it can prevent an alarm such as a hot water leak due to a malfunction and a short circuit of the induction coil, melting damage, and water leak. And the structure of the side wall of the crucible induction furnace.

[0002]

2. Description of the Related Art A steel sheet whose surface is plated with a low melting point metal such as zinc or tin is widely used. In particular, the galvanized steel sheet is JIS G 330 which is hot-dip galvanized.
It is widely used as a zinc-iron plate according to 2 or a colored zinc-iron plate according to JIS G 3312 for roofs, building exterior plates, building corrugated plates, general use, drawing, etc., especially for construction. On the other hand, electrogalvanized steel sheets and strips according to JIS G 3313 are used for general use, automobile use, drawing and deep drawing, etc.
Mainly used for machine industry. Since hot-dip galvanized zinc iron plates, colored zinc iron plates, etc. are used for roofs, building exterior panels, etc., they are often scrapped due to dismantling of buildings, etc. It is generated in a very large amount as scrap from the factory. In order to reuse these scraps as iron resources, in the state where zinc and tin remain attached to the surface of those steel plates as scraps, they are melted using an induction electric furnace or an induction crucible furnace to remove zinc and tin. It was separated by utilizing the difference in melting temperature from iron and iron was recovered.

Zinc as a metal to be plated has a melting point of 419.5 ° C. and a boiling point of 908 ° C., whereas iron has a melting point of 1535 ° C., and the melting temperature of low carbon steel is slightly lower than that. , The actual melting temperature is 1580-1620
It is performed with some changes between ℃. Tin has a melting point of 23
Although it is low at 1.9 ° C, the boiling point is 2600 ° C, which is close to the upper limit of the melting temperature of steel, so there is little concern that an accident will occur due to evaporation. FIG. 5 is a side sectional view of an induction melting crucible furnace 40 that is usually used for melting scrap of galvanized steel sheet, and reference numeral 1 is a stamp material of refractory material as a lining which directly contacts the molten metal M, and Inviting silica (Si
O ₂ ) etc. are solidified. A refractory brick 2 is placed on the bottom of the furnace below the heat sink 3, and a heat insulating material 3 such as a mica sheet is placed on the outer periphery of the stamp material 1 and the refractory brick 2. Reference numeral 4 denotes an electrode for detecting molten metal leak, which is surrounded by the coil cement 5 having high durability and is disposed outside the heat insulating material 3 at substantially equal intervals around the periphery, and 6 is a plurality of layers on the outer periphery of the coil cement 5. The induction heating coil has a hollow tubular shape. Cooling water is introduced into the hollow portion to cool the induction heating coil, and an interlayer insulator 7 is disposed between the induction heating coils 6 for insulation.

[0004]

As described above, zinc is
In addition to having a low melting point, it also has a boiling point of 908 ° C., which is significantly lower than the melting working temperature of steel, so that zinc is vaporized and evaporated.
On the other hand, since all the materials forming the side wall of the furnace are porous, the generated zinc vapor is the innermost stamp material,
The next heat insulating material, coil cement, and the induction heating coil outside the heat insulating material reach the coil interlayer insulation, and adhere and deposit. As a result, a hot water leak alarm is issued due to a malfunction, the coil is electrically short-circuited, melting damage, water leakage, etc. occur. Heretofore, no method has been found to completely prevent these inconveniences.

[0005]

The present invention provides a low-cost, non-magnetic metal seal plate, preferably a metal or alloy such as austenitic stainless steel or brass, in the middle of a heat insulating material and coil cement. A thin plate and an insulating plate having a thickness of about 0.1 mm were arranged in a combination of the following three types to prevent zinc vapor from penetrating outward. 1) A combination of a metal seal plate and an insulating plate. 2) A sealing material made of plywood of metal and insulating plate. 3) A metal plate is spirally wound, and insulating plates are arranged at predetermined intervals in the middle so that the metal plates do not come into contact with each other.

[0006]

[Operation] A thin metal or alloy plate that has a high density and does not allow liquid or gas to pass through and an insulating plate material are stacked and spirally wound, or the metal or alloy seal material is divided into large arcs,
It is wound between the heat insulating material of the furnace body and the coil cement, and an insulating material sheet is interposed in the part where the sealing materials of metal or alloy overlap each other to prevent a short circuit, so that the zinc vapor reaches the layer of the insulating material. However, it is completely prevented from going outside. In addition, since an insulating plate is arranged in the middle of the portion where the metal or alloy sealing materials are overlapped with each other, short-circuiting between the metal or alloy sealing materials is prevented.

[0007]

1 is a side sectional view of an induction melting crucible furnace showing a first embodiment of the present invention, in which reference numeral 10 indicates the entire furnace,
Except that a plywood 11 made of austenitic stainless steel and having a thickness of 0.1 mm and a metal seal plate 8 and an insulating plate 9 shown in FIG. 2 is wound between the heat insulating material 3 and the coil cement 5,
This is the same as the conventional induction melting crucible furnace shown in FIG. As shown in FIG. 2, it is preferable that the plywood 11 be wound one or more times to form as many lap portions as possible. As the metal seal plate, a metal or alloy such as copper or brass can be used in addition to the above stainless steel, but an austenitic stainless steel thin plate is used because it has a high melting point, is non-magnetic, and is available at a low price. Is most appropriate.

FIG. 3 is a side sectional view of an induction melting crucible furnace showing a second embodiment of the present invention. Reference numeral 20 shows the entire furnace, and an austenitic stainless steel is provided between the heat insulating material 3 and the coil cement 5. A thin metal plate made of steel and having a thickness of 0.1 mm,
As shown in FIG. 4, each of the sections is formed into two arc-shaped curved surfaces each having an arc-shaped curved surface with a slightly different radius.
The arcuate curved surface plate 18b having the smaller radius is inserted inward of a so that the openings of the curved surface plate 18b are opposite to each other. Prevent short circuit. Instead of the configuration of FIG. 4, a plurality of, for example, four divisions may be used. The sealing member 21 is the same as the conventional induction melting crucible furnace shown in FIG. 5, except that a thin metal plate and an insulating plate are stacked and wound.

[0009]

EFFECT OF THE INVENTION Comparison of winding a stainless steel plate and an insulating plate as a sealing material for blocking zinc vapor on the inner circumference of the coil cement of an induction melting crucible furnace for melting scrap such as galvanized steel plate Due to its simple structure, zinc vapor generated when the steel melts penetrates through the stamp material and reaches the outer coil cement and even the induction heating coil, causing a malfunction to generate a leak alarm. Since it is possible to prevent an accident such as a short circuit, it is possible to facilitate the melting work of scraps such as galvanized steel sheets, and greatly contribute to the industry.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an induction melting crucible furnace as a first embodiment of the present invention.

FIG. 2 is a cross-sectional plan view of a zinc vapor barrier seal used in the first embodiment of the present invention.

FIG. 3 is a side sectional view showing an induction melting crucible furnace as a second embodiment of the present invention.

FIG. 4 is a cross-sectional plan view of a zinc vapor barrier seal used in the second embodiment of the present invention.

FIG. 5 is a side sectional view showing a conventional induction melting crucible furnace.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stamp material 2 Refractory brick 3 Heat insulating material 4 Electrode 5 Coil cement 6 Induction heating coil 8 Metal seal plate 9, 19 Insulation plate 10, 20 Induction melting crucible furnace 11 Plywood 18a First arc curved surface plate 18b Second arc curved surface plate 21 Seal member

Claims (4)

[Claims] 1. A stamping material or a refractory brick which is in direct contact with molten steel, a heat insulating material arranged outside thereof, and a coil cement arranged outside thereof, and is surrounded by a coil cement, so that the furnace body is located at a position close to the upper end of the furnace body. There are electrodes for detecting molten metal leakage arranged up to the upper part of the bottom wall, and hollow tubular induction heating coils arranged in multiple rows on the outer periphery of the coil cement and insulated from each other. In a crucible induction furnace for recovering iron resources by melting scrap of steel plate plated with a low melting point metal such as zinc; vapor of the low melting point metal plated on the scrap on the inner circumference of the coil cement. A low-melting metal, characterized in that a metal seal plate for insulating the metal and an insulating plate are wound in a stacked state with the metal plate being outside and having a lap portion over one turn. Crucible for melting plated steel sheets Square induction furnace. 2. A crucible-type induction furnace for melting a low-melting metal plated steel sheet according to claim 1, wherein the low-melting metal plated steel sheet is a galvanized steel sheet. 3. The crucible-type induction furnace for melting a low melting point metal-plated steel sheet according to claim 1, wherein the metal seal plate and the insulating plate are previously formed as a plywood plate. 4. A first arc-shaped curved plate having the metal seal plate on the outer side, and a first arc curved plate having a smaller radius and being on the outer side.
A second circular arc curved surface plate inserted inside the circular arc curved surface plate, and the first and second circular arc curved surface plates have a predetermined overlapping portion with their openings facing each other. The crucible-type induction furnace for melting a low-melting-point metal-plated steel sheet according to claim 1 or 2, wherein the crucible-type induction furnace is arranged as a member, and the overlapping portion is insulated via an insulating plate.