JP2913450B2 - Induction melting furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction melting furnace provided with a mechanism for preventing deformation of a heating coil due to expansion of a melting chamber.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional induction melting furnace has a cylindrical coil cement 5 formed of castable cement around a crucible-shaped melting chamber 2 formed of a refractory material 1 so as to surround the melting chamber. And a heating coil 6 in which a water-cooled copper tube is spirally wound is integrally embedded therein. Further, a plurality of return magnetic path cores 7 are radially arranged outside the heating coil 6 and are supported by a furnace frame 8.

As a material for forming the melting chamber 2, when the melting metal is a material having a high melting temperature such as cast steel, a neutral or basic refractory material 1 such as alumina having a high heat-resistant temperature is used. However, this refractory material 1 has a problem that thermal expansion is large. Furthermore, depending on the product to be cast into the tundish or the like, the casting time is long and the refractory material 1 expands significantly. For this reason, horizontal pressure is applied to the coil cement 5 surrounding the melting chamber 2, and this force is applied to the heating coil 6 buried therein, thereby causing a problem that the coil is deformed.

Further, when the refractory material 1 is worn down, after-lamming is performed to fix the powdered refractory material 1 on the upper part of the outer peripheral portion of the melting chamber 2 to repair the same, thereby extending the life of the melting furnace. However, when this repair is performed, there is a problem that the expansion of the melting chamber 2 is further increased and the coil deformation is increased. For this reason, the return path iron core 7 provided on the outer periphery of the heating coil 6
To increase the force for suppressing the deformation from the outside, or as shown in FIG.
The thickness of the cushion material 4 interposed therebetween is increased to take measures to absorb thermal expansion. However, increasing the number of the return path cores 7 increases the weight and cost of the induction melting furnace, and increasing the thickness of the cushioning material 4 increases the distance between the molten metal 9 and the heating coil 6 to increase the heating efficiency. There is a problem that becomes worse.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an induction melting furnace which eliminates the above-mentioned disadvantages and prevents deformation of a heating coil due to expansion of a refractory material forming a melting chamber.

[0006]

SUMMARY OF THE INVENTION The present invention provides an induction melting furnace in which a cushion material is interposed between the outer periphery of a crucible-shaped melting chamber and the inner periphery of a coil cement surrounding the melting chamber. The present invention is characterized in that a tapered surface inclined upward to the heating coil side is formed on the inner peripheral wall surface of the coil cement, and the cushion material is made of a slippery material. Further, the present invention is characterized in that the angle of the tapered surface is inclined by 0.2 to 4 degrees with respect to a vertical line.

[0007]

In the induction melting furnace of the present invention, when the melting chamber expands outward due to thermal expansion, a tapered surface inclined upward to the heating coil side is formed on the outer peripheral wall surface and the inner peripheral wall surface of the coil cement. Further, since a cushion material made of a slippery material is interposed here, the pressure of the expanded melting chamber escapes upward, the melting chamber slides upward along the tapered surface, and the heating coil surrounding the tapered surface. Can be prevented from being deformed. Further, by defining the inclination angle of the tapered surface in the range of about 0.2 to 4 degrees with respect to the vertical line, the upward movement of the melting chamber due to thermal expansion can be promoted.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. As shown in FIG. 3, a coil cement 5 made of castable cement is provided around a crucible-shaped melting chamber 2 formed of a refractory material 1 through a cushion material 4 so as to surround the melting chamber 2. A heating coil 6 in which a copper tube is spirally wound is embedded integrally.
Further, a plurality of return magnetic path cores 7 are radially arranged outside the heating coil 6 and are supported by a furnace frame 8.
The configuration so far is the same as that of the conventional induction melting furnace.

Further, according to the present invention, as shown in FIG. 1, a tapered surface 10 inclined upward to the heating coil 6 side is formed on the outer peripheral wall surface of the melting chamber 2 and the inner peripheral wall surface of the coil cement 5. The cushioning material 4 has a surface on the melting chamber 2 side formed by laminating a slippery material such as a mica sheet 3 and a glass woven fabric. The inclination angle α of the tapered surface 10 is inclined in the range of 0.2 to 4 degrees with respect to the vertical line V.

[0010] In the induction melting furnace having the above-described structure, when melting a material having a high melting temperature for a long time, a neutral or basic refractory material 1 having a high heat-resistant temperature is used, which has a large thermal expansion. When the melting chamber 2 expands outward due to thermal expansion,
A tapered surface 10 inclined upward to the heating coil 6 side is formed on the outer peripheral wall surface and the inner peripheral wall surface of the coil cement 5, and a cushion material 4 made of a slippery material is interposed here. Therefore, the expanded dissolution chamber 2 is shown in FIG.
As shown in the figure, the pressure escapes upward and the melting chamber 2 is tapered.
Sliding upward along 10 and no large horizontal pressure is applied to the coil cement 5 surrounding it, the deformation of the heating coil 6 can be prevented.

When the melting chamber 2 has been damaged, after-lamming is performed to fix the powdered refractory material 1 on the upper portion of the outer peripheral portion to repair the melted refractory material 1, and the thermal expansion of the melting chamber 2 is further increased. Even so, the horizontal pressure applied to the heating coil 6 can be released. Accordingly, it is not necessary to increase the thickness of the cushion material 4, so that the heating efficiency does not decrease, and the number of the return path iron cores 7 does not need to be increased.
The weight can be reduced.

The inclination angle α of the tapered surface 10 formed on the outer peripheral wall surface of the melting chamber 2 and the inner peripheral wall surface of the coil cement 5 is 0.2 to 4 degrees with respect to the vertical line V, and particularly 0.5 to 0.9. The range of the degree is desirable, and if it is less than 0.2 degree, the sliding effect is small,
The horizontal pressure due to the expansion of the melting chamber 2 may be applied to the heating coil 6 to deform it, and if the inclination angle is larger than 4 degrees, the construction is troublesome.

[0013]

As described above, according to the induction melting furnace of the present invention, a tapered surface is formed on the outer peripheral wall surface of the melting chamber and the inner peripheral wall surface of the coil cement, and the tapered surface is formed along the tapered surface by expansion of the melting chamber. Since it slides upward, a large horizontal pressure is not applied to the coil cement surrounding it, thereby preventing deformation of the heating coil and performing stable operation for a long period of time. Further, by defining the inclination angle of the tapered surface, the upward sliding due to the expansion of the melting chamber is promoted, and the deformation of the heating coil can be more reliably prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an induction melting furnace having tapered surfaces formed on an outer peripheral wall surface of a melting chamber and an inner peripheral wall surface of a coil cement according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view of the induction melting furnace showing a state where the melting chamber shown in FIG. 1 is expanded and slid upward.

FIG. 3 is a sectional view showing an induction melting furnace.

FIG. 4 is an enlarged sectional view showing a joining portion between a melting chamber and a coil cement of a conventional induction melting furnace.

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 Refractory material 2 Melting room 4 Cushion material 5 Coil cement 6 Heating coil 7 Return magnetic core 8 Furnace frame 9 Molten metal 10 Tapered surface

Claims (2)

(57) [Claims] 1. An induction melting furnace in which a cushion material is interposed between an outer periphery of a crucible-shaped melting chamber and an inner circumference of a coil cement surrounding the melting chamber, wherein an upper wall surface of the melting chamber and an inner peripheral wall surface of the coil cement are arranged upward. An induction melting furnace characterized by forming a tapered surface inclined toward a heating coil toward the heating coil and comprising a cushion material of a slippery material. 2. The angle of the tapered surface is set at 0.
2. The induction melting furnace according to claim 1, wherein the furnace is inclined by 2 to 4 degrees.