JPH0293288A - Melting device - Google Patents

Abstract

PURPOSE:To melt minute materials such as Sendalloy and facilitate the adjustment of the melting temperature, melting speed and compositions by disposing an electromagnetic coil around the external surface of the furnace wall to subject a heater to electromagnetic induction heating. CONSTITUTION:The furnace body 1 is lined with refractory material, and coils 2b, 2c, 2d are supplied with power while coils 2a, 2e are not. Lumps 6 of black lead which is electrically conductive and refractory are induction-heated by the coils 2b, 2c, 2d. The material 7 is melted by the radiation heat from the black lead lumps 6 and a small quantity of high-temperature gas which is generated by the reduction of the oxides, and is heated and reduced as it drops through the gaps between the black lead lumps 6 to be discharged from the outlet 5. This way, even if the material 7 is in the form of powder which cannot be normally used in cupola or if it has been oxidized, it can be efficiently melted. When the grain size of the material 7 is suitable for the induction heating, the material itself generates heat due to the electromagnetic induction, resulting in the efficient melting.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a melting device, and in particular to a melting device that has a large reducing ability that can dissolve even oxidized fine powder materials and that allows easy control of melting temperature and dissolution rate. Regarding.

[Conventional technology]

For example, cupola and crucible furnaces are well known and widely used as conventional cast iron melting devices. Cupola allows you to continuously obtain well-refined, high-quality molten metal.
It is a so-called continuous melting furnace, and the crucible furnace is a so-called intermittent melting furnace in which the melting temperature and components can be easily adjusted. Each method has its advantages and disadvantages, and a dual dissolution method using a combination of these methods is also widely used. Note that related devices of this type include, for example, Japanese Patent Publication No. 52-48564.

[Problem to be solved by the invention]

Cupolas require the blowing of a large amount of air to burn coke, which is a carbonaceous substance, at high temperatures, and have the following disadvantages.

(1) Extra heat is required to heat the air, and the higher the temperature becomes, the lower the thermal efficiency is because CO2 in the combustion generated gas is reduced again to CO by coke.

(2) The gas flow rate in the furnace is high, and fine materials such as pig iron cannot be melted because they are discharged outside the melting device by the gas flow before being melted.

(3) Because heat is exchanged between the high-temperature and high-velocity combustion gas and the material, a large amount of material is required during preheating, and it takes time to melt the material, resulting in a slow response speed. It is very difficult to change or adjust the ingredients.

(4) Because coke is continuously melted by combustion, it is almost impossible to change or stop the melting rate while maintaining a constant temperature and components.

On the other hand, crucible furnaces have advantages such as being able to use any materials and being easy to control the components, but they are basically an intermittent melting method and have problems such as the need for a starting lock at the start. Furthermore, since melting is performed by simply induction heating of the material, there is a problem in that scouring effects such as reduction cannot be expected. Furthermore, it is inconvenient to feed molten metal to continuous casting equipment.

The object of the present invention is to provide a melting apparatus which can use not only pig iron but also fine oxidized materials, and which can adjust the temperature, the components contained, and the dissolution rate.

[Means to solve the problem]

The above purpose is to provide a melting device that consists of a heating element made of a conductive refractory material serving as a heat source and a furnace wall housing the heating element, and in which a predetermined material passes between the heating elements after melting.
This is achieved by providing a coil outside the furnace wall and heating the heating element by electromagnetic induction.

[Effect]

For example, although sunspot, which is a conductive refractory, has a higher electrical resistance than metals such as cast iron, it can be sufficiently heated with medium-frequency induction heating, so graphite in the melting zone can be heated by means other than combustion. . In addition, even if the position of the melting zone changes, the width of the coil's soaking zone can be expanded or moved, allowing power to be concentrated in the melting zone that requires the most energy, resulting in more efficient melting. be able to.

Furthermore, by increasing/decreasing the input and moving the soaking heating zone of the coil, it is possible to easily obtain work patterns of high-temperature large quantity, high-temperature small quantity, low-temperature large quantity, and low-temperature small quantity.

The materials to be melted are not limited to cast iron, but can be used to melt and reduce various metals that can be reduced with carbon.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1st
The figure is a longitudinal sectional view of the melting device. The melting device is furnace body 1,
It consists of coils 2a, 2b, 2c, 2d, and 2e. Furnace body 1
are lined with refractory material, and in FIG. 1, coils 2b, 2c, and 2d are energized, and coils 2a, 2e are
is not energized. The graphite lump 6, which is a conductive refractory, is heated by induction by the coils 2b, 2c, and 2d, and the material 7 is melted by the radiant heat of the graphite lump 6 and a small amount of reducing high temperature gas generated by reduction of oxides, etc. It falls through the gap between the lumps 6, is further heated and reduced, and is discharged from the tap 5. In this way, even powdered materials that cannot normally be used in cupolas or oxidized materials can be efficiently dissolved. Furthermore, if the size of the material 7 is sufficient for induction heating, the material itself will generate heat due to electromagnetic induction, and it goes without saying that it can be melted more efficiently.

If you want to increase the dissolution rate, disconnect switch 3b from power supply section 4 and connect it to coil 2a, connect switch 3a to power supply section 4 instead, and disconnect switch 3e from power supply section 4. It is preferable to disconnect and open the switch 3d and connect the changeover switch 3d to the power supply section 4 instead to increase the input. Conversely, if you want to reduce the dissolution rate,
The changeover switch 3b is disconnected from the power supply part 4 and opened, and the changeover switch 3c is connected to the power supply part 4 instead, and the changeover switch 3e is disconnected from the power supply part 4 and connected to the coil 2e, and the changeover switch 3f is opened instead. It is only necessary to connect the power supply unit 4 to the power supply unit 4 to reduce the input.

As is clear from these examples, in the present invention, the temperature of the melting zone can be freely adjusted by changing the connections and inputs of the coils 2a, 2b, 2c, 2d, and 2e, and therefore the tapping temperature and melting rate can be adjusted. is easy to control. Furthermore, the material pre-heating period can be made very short;
The time from adding materials to tapping the water is short, feedback is easy, and the ingredients can be easily adjusted.

Further, in one or more of the embodiments, the case where there is no ventilation hole has been described, but in the present invention, the ventilation hole is not limited to air, and it is also possible to blow inert gas or the like.

In the above description, the case where graphite lump 4 is used has been described, but the present invention is not limited to this, and conductive refractories can be used. Furthermore, the present invention is not limited to continuous melting, and it goes without saying that the tap can be temporarily closed to perform intermittent melting.

The table shows the analysis results in percentage of the main components of the molten metal obtained by this method using pig iron, Fe2O, (red iron), fine punching scraps of electrical steel sheets, and glass shavings from castings as raw materials.

It is possible to easily adjust the dissolution temperature, dissolution rate and components.

Furthermore, a material such as Fe2O□, which is an oxide, can be reduced by heated graphite and a reducing atmosphere, resulting in the effect that a high-quality molten metal can be obtained.

[Brief explanation of the drawing]

The figure is a sectional view showing the configuration of an embodiment of the present invention. 1... Furnace body, 2... Coil, 3... Selector switch,
4... Power supply part, 5... Tap water outlet, 6... Graphite lump, 7
···material. /-m-Hearth 2--Coil 3-t7J Ichisuinna Rei-#-Takube 5-Shuku Yuguchi 6-J, Katatamasu 7-Hane'to

Claims (1)

[Claims] 1. A melting device consisting of a heating element made of a conductive refractory material serving as a heat source and a furnace wall housing the heating element, in which a predetermined material passes between the heating elements after melting. A melting apparatus characterized in that a coil is provided outside the furnace wall, the heating element is heated by electromagnetic induction, and a soaking zone of the coil is movable in the axial direction of the coil. 2. In the dissolving device according to claim 1, a plurality of (
A melting device characterized in that (n) coils are divided and arranged in the axial direction, and selected (n-m) adjacent coils are connected to each other and a current is passed through the selected coils. 3. In a melting device that consists of a heating element made of a conductive refractory material that serves as a heat source and a furnace wall that houses the heating element, and which passes between the heating elements after a predetermined material is melted, the outside of the furnace wall A melting device comprising: a coil for heating the heating element by electromagnetic induction; and the coil is partially made densely. 4. The melting device according to claim 3, characterized in that the coil is set densely at both ends and coarsely at the center.