JPH04187987A - Melting vessel for induction furnace and melting method for different kinds of metals - Google Patents

Abstract

PURPOSE:To provide a melting vessel capable of continuously melting a plurality of kinds of metals by a method wherein the melting vessel comprises a mica layer formed of mica sheets laminated on the inner side of a thick base layer formed of a refractory material and a thin surface layer laminated on the inner side of the mica layer and formed of a refractory material. CONSTITUTION:A melting vessel 20 comprises a base layer 22, a mica layer 24, and a surface layer 26. When a plurality of kinds of metals different in a composition are continuously molten, after a first metal is molten in the melt vessel 20, a second metal having a different composition is molten. In this case, the surface layer 26 is broken and removed from the melt vessel 20, and the mica layer 24 is shaved off from the base layer 22. A new mica lay sheet is adhered and stuck to the base layer 20 to form a mica layer 24, and after a prebaked cupform surface layer 26 is engaged and fixed in an adhered state, a second metal is molten, and in a subsequent metal also, the aboves are repeated. Since the mica sheet insulates a metal, though a molten metal soaks into the surface layer 26, it does not soak into the base layer 22. As a result, a plurality of kinds of metals needing purity but different in a composition can be continuously molten.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a melting tank (usually formed inside an asbestos plate or the like inside a coil) in an induction furnace such as a crucible type (coreless type) that does not use an iron core. The present invention relates to a method for melting dissimilar metals using the melting tank.

[Prior Art] A melting tank used in a conventional crucible-type induction furnace will be described with reference to FIG.

In the figure, reference numeral 2 denotes a coil disposed in the furnace shell 4, both ends of which are connected to an AC power source (not shown). A cylindrical melting tank 8 with an open top and a bottom is disposed on the inner circumference of the coil 2 with the asbestos 6 interposed therebetween.
The lower end of is buried in the refractory layer IO. This dissolution tank 8
is made of a refractory material whose main component is magnesia.

When melting metal, place the metal to be heated in the melting tank 8 and apply an alternating current of a predetermined frequency to the coil 2. The metal will melt due to heat generated by eddy current loss caused by electromagnetic induction. do.

[Problems to be Solved by the Invention] When multiple types of metals with different compositions are continuously melted using the conventional melting tank as described above, in order to wash away the metals that adhered to the melting tank during pre-melting, The method used is to wash the dissolution tank with common metal. That is, a metal to be used as a co-metal is placed in the melting tank 8 and melted once, and the melted metal is used to wash away the metal adhered to the inner wall of the melting tank 8 during the pre-melting process, and then the target metal is melted.

However, the above method has the disadvantage that it consumes valuable metals, electricity, etc., and is time-consuming and expensive. Furthermore, the above method cannot be used to melt metals that require purity, such as pure cobalt and pure nickel. This is because when metal is melted in the melting tank 8,
Because some of the melted metal seeps into the melting tank 8,
Even if the inner surface of the melting tank 8 is cleaned with co-metal, the metal that has seeped into the inside of the melting tank 8 during the pre-melting process can be completely removed, and this residual metal will seep out from the melting tank 8 when the target metal is melted. This is the waste that gets mixed into the target metal.

As a method to compensate for the above defects, there are methods such as breaking and removing the melting WI 8, rebuilding it and lining it to form the melting tank 8, and replacing the furnace body together with the furnace shell 4, but both methods require time and effort. It has the disadvantage of being too expensive.

The present invention aims to solve such problems.

[Means for Solving the Problems] In the first aspect of the invention, the melting tank installed inside the coil is made of a thick base layer made of a refractory material and a mica plate laminated inside the base layer. This is a melting tank for an induction furnace, characterized in that it is formed of a mica layer made of the above mica layer, and a thin surface layer made of a refractory material laminated inside the mica layer.

The invention of claim 2 provides that when a second metal having a different composition from the first metal is melted after melting the first metal in the melting tank described in claim 1, the mica layer and This is a dissimilar metal melting method in which after the surface layer is removed, a mica layer and a surface layer are deposited on the base layer again to repair the melting tank, and then the second metal is melted.

The invention of claim 3 is the dissolution tank according to claim 1,
When melting specific metals, the surface layer and mica layer are removed from the melting tank, and when melting non-specific metals that have a different composition from the specific metal, the mica layer and surface layer are deposited on the base layer. This is a method of melting dissimilar metals in which melting is performed with the melting tank repaired.

[Function] In the melting tank of the first claim, when metal is melted, the molten metal is insulated by the mica layer and does not penetrate into the base layer, and even if there is residual metal in the base layer, the residual metal is absorbed by the mica layer. It is insulated and does not seep into the surface layer. Furthermore, since the surface layer is thin, it is inexpensive to produce.

[Example] A melting tank for an induction furnace according to the present invention will be described with reference to FIG. Components in this figure that are the same as those in FIG. 2 are designated by the same reference numerals, so their explanations will be omitted.

In the figure, reference numeral 20 indicates a dissolution tank according to this embodiment,
It is composed of a base layer 22, a mica layer 24, and a surface layer 26.

Similar to the dissolution tank 8 in FIG. . The base layer 22 is made of a refractory material such as magnesia, and is formed to have the same thickness as a conventional melting tank, that is, to maintain the strength of the structure.

The mica layer 24 is made of a mica plate with a thickness of just under 1R11, and is laminated closely inside the base layer 22.

The surface layer 26 is made of the same refractory material as the base layer 22, has a thinner wall thickness than the base layer 22, and is closely laminated inside the mica layer 24. The inner surface of this surface layer 26 becomes the inner surface of the dissolving tank 2o.

The method of melting a single metal using the melting tank 20 having the above configuration is completely the same as the conventional method, and is carried out by passing an alternating current of a predetermined frequency through the coil 2.

Next, a case will be described in which a plurality of metals (requiring purity) having different compositions are continuously melted using the melting tank 20.

The first metal (hereinafter referred to as "first metal") is melted into the melting tank 2.
After melting in the melting tank 2, when melting the next metal with a different composition (hereinafter referred to as "second metal"), first melt the metal in the melting tank 2.
The surface layer 26 is broken down and removed from the base layer 20, and the mica layer 24 is then scraped off from the base layer 20. Next, a new mica plate is closely attached to the base layer 20 again to form a mica layer 24. A cup-shaped surface layer 2 that has been fired in advance on this mica layer 24
6, and fix it in a tight state, and restore it to the state shown in FIG. 1 again.

Thereafter, the second metal is melted in the same manner as the first metal, and the same process as above is repeated for the next metal.

In the dissolving layer 20 according to this embodiment, the mica plate has the function of insulating (separating) the metal. It never really sinks in. Therefore, the metal during pre-melting does not seep out from the base layer 22, and metals that require purity can be reliably melted. In addition, mica (mica) has strong heat resistance, so the mica layer 24 will not weld to the base layer 22 and the surface layer 26, and even if the base layer 22 and the surface layer 26 expand thermally, slipping will occur between the mica layer and the mica layer. The t1 melting tank 20 will not be damaged by the heat of melting.

Furthermore, since the surface layer 26 does not need to have strength as a structure and may be thinner than the base layer 22, the melting tank 26
It is not very expensive to repair, and it is also easy to repair.

In addition, in my explanation above, I showed how to replace the mica layer 24 and the surface layer 26 with new ones each time the metal to be melted changes, but if the mica layer 24 and the surface layer 26 are replaced with new ones each time the metal to be melted changes, In some cases, when melting a specific metal, the mica layer 2 is always removed from the melting tank 20.
4 and the surface layer 26 have been removed, that is, only the base layer 22 may be melted. When melting a metal (non-specific metal) that has a different composition from the specific metal, the mica layer 2
4 and the surface layer 26 are repaired, the melting may be performed. As a result, the specific metal will seep into the base layer 22. However, when melting the specific metal, there is no problem even if the specific metal that has soaked into the base layer 22 seeps out. When melting non-specific metals, the mica layer 24 Since the specific metal soaked into 22 is insulated, no contamination occurs. By doing this, the mica layer 24 and the surface layer 2
It is possible to save the effort and expense of repairing 6.

[Effect of the invention] By using the dissolving layer of the first claim in the method of the second or third claim, it is possible to continuously produce multiple types of metals with different compositions that require purity easily and at low cost. The effect of dissolving is obtained.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view showing a melting chamber of a conventional induction furnace. 2...Coil, 20...Dissolution tank, 22...
... Base layer, 24 ... Mica layer, 26 ...
surface.

Claims (3)

[Claims] (1) A melting tank installed inside the coil is made of a thick base layer made of a refractory material, a mica layer made of a mica plate laminated inside the base layer, and a mica layer laminated inside the mica layer. A melting tank for an induction furnace characterized by being formed with a thin surface layer made of refractory material. (2) When dissolving a second metal having a different composition from the first metal after melting the first metal in the melting tank according to claim 1, after removing the surface layer and the mica layer from the melting tank, A method for melting dissimilar metals, in which a mica layer and a surface layer are deposited on the base layer again to repair the melting tank, and then a second metal is melted. (3) In the melting tank according to claim 1, when specific metals are melted, the surface layer and mica layer are removed from the melting tank, and when non-specific metals having a different composition from the specific metals are melted. This is a method of melting dissimilar metals in which a mica layer and a surface layer are deposited on the base layer and the melting tank is repaired before melting.