JP2002327989A - Induction heating water-cooled crucible furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an induction heating water-cooled crucible furnace, in which the furnace construction is improved to melt easily a metal of high electric-conductivity or high thermal-conductivity, such as copper or silver. SOLUTION: A carbon-made cylindrical body 12 of 3-50 mm thick is placed on the inner wall face of the crucible 1, and the carbon is heated by alternating magnetic field to a high temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating water-cooled crucible furnace capable of melting a metal having high electric conductivity and high heat conductivity such as copper and silver.

[0002]

2. Description of the Related Art Generally, a furnace for supplying a high-frequency or medium-frequency current to a coil disposed on the outer periphery of a water-cooled crucible made of metal such as copper to melt the metal to be melted contained in the crucible by induction heating;
That is, the induction heating type water-cooled crucible furnace has a structure as shown in FIG. In this induction-heated water-cooled crucible furnace, the melted metal does not contact the inner wall of the crucible, but only in the lower part,
Since a solidified portion (skull portion) is formed only at the so-called cooled bottom portion, contamination of the material to be melted from the crucible can be prevented as much as possible, so that it is used for melting high-purity metal. It is also called "skull furnace" because of the formation of the skull.

[0003] The general structure of a conventional induction-heating water-cooled crucible furnace will be described.
2, a bottom wall 23 and a crucible bottom 24. Water-cooled copper crucible 21
Coil 2 for supplying high-frequency or medium-frequency current
5 are installed. Below the side wall of the crucible is provided a radially extending flange 26, while a similar overhang 27 is also provided at the bottom of the crucible, the two overhangs 26, 27 being connected by bolts. A plurality of vertically extending grooves (slits) 28 are formed in the side wall of the crucible, and are separated into a plurality of longitudinal segments 29. The structure including the plurality of segments 29 in which such slits are formed acts to easily pass the magnetic flux and increase the magnetic flux density.

A water cooling pipe 30 is provided inside each segment 29, and cools the side wall 22 and the bottom wall 23 of the crucible through a pipe 31 of the crucible bottom 24. The to-be-dissolved metal 32 introduced into the crucible is melted by being exposed to an alternating magnetic field due to a high-frequency or medium-frequency current applied to the coil 25. In this case, due to the field balance between the electromagnetic force acting on the surface of the molten metal and the static pressure of the molten metal, the upper part of the crucible is separated from the molten metal 32 from the side wall of the crucible as shown in FIG. Partially solidified only below the wall contacting 33
Take the structure to do. That is, the metal is melted into an egg shape. This is a major feature of the induction heating water-cooled crucible furnace. Most of the melting metal does not come into contact with the side wall of the crucible, and even when it does, the solidified shell (skull) 33 of the melting metal can prevent contaminants from entering the inside from the side wall 22 of the crucible. Therefore, melting and casting of a high-purity metal is possible.

[0005] The induction-heated water-cooled crucible furnace 21 described above.
Metals with relatively low electrical and thermal conductivity, such as titanium and cobalt, can be dissolved without problems, but metals with high electrical and high thermal conductivity, such as copper and silver, cannot be easily dissolved. Even if it is melted, there is a problem that it immediately solidifies from the part touching the water-cooled crucible. Although such an induction-heating water-cooled crucible furnace 21 has the feature that it is most suitable for melting and casting of high-purity metal, it can melt only a specific metal, and there is a limit to the metal material that can be melted. There were drawbacks.

[0006]

SUMMARY OF THE INVENTION The present invention improves the structure of a water-cooled crucible of an induction heating type as described above, and can easily dissolve metals having high electrical conductivity and high thermal conductivity such as copper and silver. An object of the present invention is to provide an induction heating type water-cooled crucible furnace.

[0007]

The present invention provides: 1. An induction-heating water-cooled crucible furnace characterized by having a carbon cylinder placed on the inner wall surface of the crucible. The induction-heated water-cooled crucible furnace according to claim 1, wherein the thickness of the cylindrical body is 3 to 50 mm.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of an induction heating type water-cooled crucible furnace of the present invention will be described with reference to FIG. The induction-heated water-cooled crucible furnace of the present invention can use a conventional induction-heated water-cooled crucible furnace as it is, or can be formed integrally with a carbon cylinder described later on the inner wall surface of the crucible. FIG. 1 shows an example in which the induction-heated water-cooled crucible furnace of the present invention is used. A water-cooled copper crucible 1 as a furnace body includes side walls 2, a bottom wall 3, and a crucible bottom 4. A coil 5 for supplying a high-frequency or medium-frequency current is provided on the outer periphery of the water-cooled copper crucible 1. A flange 6 extending radially below the side wall of the crucible is provided, and the flange and an extension 7 of the crucible bottom 4 are connected by bolts. A plurality of vertically extending grooves (slits) 8 are formed in the side wall of the crucible and are divided into a plurality of longitudinal segments 9 as in the prior art.

A water cooling tube 10 is provided inside each segment,
The side wall 2 and the bottom wall 3 of the crucible 1 are cooled through the pipe 11 of the crucible bottom 4. In such an induction heating type water-cooled crucible furnace 1, the present invention is characterized in that a carbon cylinder 12 is provided on the inner wall surface of the crucible 1. The carbon cylinder 12 is exposed to an alternating magnetic field by a high-frequency or medium-frequency current applied to the coil 5 and is heated to a high temperature, and the metal 13 introduced into the crucible 1 is easily melted by this heat. This dissolvable metal can be dissolved regardless of the level of electrical conductivity or thermal conductivity.

However, since the molten metal 13 existing in the carbon cylinder 12 is exposed to an alternating magnetic field due to a high-frequency or medium-frequency current around it, a part of the molten metal 13 comes into contact with the carbon via a water-cooled crucible. Solidifies, but hardly contacts its surroundings. Due to the field balance between the electromagnetic force acting on the surface of the molten metal and the static pressure of the molten metal, the inner wall of the carbon cylinder 12 and the molten metal 13 are separated above the crucible 1 as shown in FIG. For example, it has a structure that is partially solidified only below the metal bottom wall 2 made of copper or the like. That is, the metal is similarly melted into an egg shape.

Most of the metal 13 to be melted does not come into contact with the cylindrical body 12 made of carbon, and even when it is in contact therewith, the solidified shell (skull) 14 of the metal to be melted causes the metal 13 to be removed from the cylindrical body 12 made of carbon. Since the intrusion of contaminants into the interior can be suppressed to a minimum, high purity metal can be melted and cast.
Therefore, even a metal having high electrical conductivity and high thermal conductivity such as copper and silver can be easily melted by the induction-heating water-cooled crucible furnace 1 in which the carbon cylinder 12 is provided on the inner wall surface of the crucible of the present invention. It has an excellent effect. The thickness of the carbon cylinder 12 is 3 to 50 mm. 3m
If the thickness is less than m, the strength is weak, and if the thickness exceeds 50 mm, melting can be performed. However, since the electromagnetic force does not penetrate into the metal inside the carbon cylinder 12, the molten metal does not rise and comes into contact with the carbon cylinder. Therefore, the thickness is in the range of 3 to 50 mm.

[0012]

Examples and Comparative Examples Next, description will be made based on Examples and Comparative Examples. Note that these are intended to facilitate understanding of the present invention, and the present invention is not limited to these.

(Example 1) A crucible equivalent to the water-cooled copper crucible shown in FIG. 1 was used, and a 10 mm-thick carbon cylinder was mounted in the crucible. Copper was melted using this water-cooled copper crucible. The frequency is 1 kHz. A conceptual diagram of this dissolution is shown in FIG. As shown in FIG. 2, the molten metal 18 is placed in the crucible 15
The inner part was melted and held in an oval shape, and complete dissolution was achieved only by making contact with a small portion of the inside of the carbon-made cylindrical body 16 having a thickness of 10 mm. A skull 17 was formed at the bottom.

(Comparative Example) As in Example 1, a crucible equivalent to the water-cooled copper crucible shown in FIG. 1 was used, and copper was melted without disposing a carbon cylinder in the crucible. The frequency is also 1
kHz. A conceptual diagram of this dissolution is shown in FIG. According to this, heat is removed from the portion where the melted metal has touched the water-cooled copper crucible 19 and further melting does not proceed. As a result, a phenomenon occurs in which only the copper surface is melted, and the desired melting is not sufficiently performed. could not. Reference numeral 20 shown in FIG. 3 is a molten (molten metal) portion, and reference numeral 21 is an undissolved portion inside.

[0015]

As described above, an induction-heated water-cooled crucible furnace in which a carbon-made cylinder is installed on the inner wall surface of the crucible of the present invention can also be used to produce a metal having high electrical conductivity and high thermal conductivity such as copper and silver. It has an excellent effect that it can be easily dissolved.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view of an induction heating water-cooled crucible furnace in which a carbon cylindrical body is installed on the inner wall surface of a crucible according to an example of the present invention.

FIG. 2 is a conceptual diagram of dissolution shown in an example.

FIG. 3 is a conceptual diagram of dissolution shown in a comparative example.

[Explanation of symbols]

 1, 15, 19 crucible 2 side wall 3 bottom wall 4 crucible bottom 5 coil 6 flange 7 overhang 8 slit 9 segment 10 water cooling pipe 11 pipe 12 carbon cylindrical body 13, 18, 20 molten metal 14, 17 solidified shell (skull) ) 21 Undissolved part

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[Procedure amendment]

[Submission date] June 15, 2001 (2001.6.1)
5)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0003

[Correction method] Change

[Correction contents]

[0003] The general structure of a conventional induction-heated water-cooled crucible furnace will be described . As shown in FIG. 2, a water-cooled copper crucible 15 as a furnace body has a side wall, a bottom wall, and a crucible bottom. A coil for supplying a high-frequency or medium-frequency current is provided on the outer periphery of the water-cooled copper crucible 15 . Below the side wall of the crucible is provided a radially projecting flange, while a similar overhang is provided at the bottom of the crucible, which are bolted together. A plurality of vertically extending grooves (slits) are formed in the side wall of the crucible, and are separated into a plurality of longitudinal segments. The structure consisting of a plurality of segments in which such a slit is formed,
It functions to easily pass the magnetic flux and increase the magnetic flux density. This
Such a structure, except for a carbon cylinder described later,
It has a structure similar to that of FIG.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

A water cooling pipe is provided inside each segment, and cools the side wall and the bottom wall of the crucible through a pipe at the bottom of the crucible. The metal to be melted introduced into the crucible is exposed and melted by an alternating magnetic field caused by a high-frequency or medium-frequency current applied to the coil. In this case, due to the field balance between the electromagnetic force acting on the surface of the molten metal and the static pressure of the molten metal, the molten metal 18 is separated from the side wall of the crucible at the upper part of the crucible as shown in FIG. It takes a structure that partially solidifies 17 only below the wall in contact with the wall. That is, the metal is melted into an egg shape. This is a major feature of the induction heating water-cooled crucible furnace. Most of the melting metal does not come into contact with the side wall of the crucible, and even when it does, the solidified shell (skull) 17 of the melting metal can prevent contaminants from entering the inside from the side wall 16 of the crucible. Therefore, melting and casting of a high-purity metal is possible.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

[0005] The induction-heated water-cooled crucible furnace 15 described above.
Metals with relatively low electrical and thermal conductivity, such as titanium and cobalt, can be dissolved without problems, but metals with high electrical and high thermal conductivity, such as copper and silver, cannot be easily dissolved. Even if it is melted, there is a problem that it immediately solidifies from the part that touches the water-cooled crucible. Such an induction-heated water-cooled crucible furnace 15 is capable of melting only a specific metal, and has a limitation in the metal material that can be melted, although it has the feature of being optimal for melting and casting of high-purity metal. There were drawbacks.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction contents]

[0006]

SUMMARY OF THE INVENTION The present invention improves the structure of a water-cooled crucible of an induction heating type as described above, and can easily dissolve metals having high electrical conductivity and high thermal conductivity such as copper and silver. so
The present invention provides a water-cooled crucible furnace of the induction heating type.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

(Comparative Example) As in Example 1, a crucible equivalent to the water-cooled copper crucible shown in FIG. 1 was used, and copper was melted without disposing a carbon cylinder in the crucible. The frequency is also 1
kHz. A conceptual diagram of this dissolution is shown in FIG. According to this, heat is removed from the portion where the melted metal has touched the water-cooled copper crucible 15 and further melting does not proceed. As a result, a phenomenon occurs in which only the copper surface is melted, and the desired melting is not sufficiently performed. could not. Reference numeral 20 shown in FIG. 3 is a molten (molten metal) portion, and reference numeral 21 is an undissolved portion inside.

Claims (2)

[Claims] 1. An induction-heating water-cooled crucible furnace, wherein a carbon cylindrical body is provided on the inner wall surface of the crucible. 2. The induction-heated water-cooled crucible furnace according to claim 1, wherein the thickness of the cylindrical body is 3 to 50 mm.