JPH07318254A - High frequency induction melting furnace - Google Patents

Abstract

PURPOSE:To prevent slag from being mixed into molten slag generated within a melting crucible by a method wherein a molten metal port having a semi-circular section oppositely faced against an opening part in an upper end surface of the melting crucible and having its one end connected to the outer peripheral part of the melting crucible and then a molten metal discharging hole for discharging molten metal is formed at a part near a connection part of the molten metal port with the melting crucible. CONSTITUTION:In the case that molten metal 22 is discharged out of a melting crucible 8, a melting furnace frame is rotated by a motor more than 90 deg. so as to be set to a state shown in B. Under this state, molten metal 22 is moved toward a molten metal port 21 and slag 23 floats up to an upper layer of the molten metal 22 within the molten metal port 21. Concurrently, only the molten metal 22 into which the slag 23 is not mixed is discharged from the molten metal discharging hole 21c into a casting mold. Accordingly, it is possible to prevent slag 23 from entering the metal and to discharge out only superior molten metal 22 through a simple structure in which the molten metal feeding port 21 having a substantial semi-circular section is arranged at a releasing end of the melting crucible 8, resulting in that a superior casted product having no defects can be manufactured and quality of the product can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency induction melting furnace for melting metals and alloys such as special steel, cast steel and copper by induction heating. Induction melting furnace.

FIG. 3 shows the configuration of an example of a conventional high frequency induction melting furnace as described above. In FIG. 3, a tilting shaft 3 is rotatably supported on a pedestal 1 via a pair of bearings 2. Both sides of a box-shaped melting furnace frame 4 facing each other are attached to the tilting shaft 3, and a cylindrical melting furnace body 5 is mounted and fixed in the melting furnace frame 4. A motor 6 is installed on the upper surface of one side of the gantry 1, and an output shaft 7 of the motor 6 is concentrically connected to the tilting shaft 3.

A melting crucible 8 having a substantially bottomed cylindrical shape is arranged at the center of the melting furnace body 5, and a coil 9 is concentrically wound around the outer circumference of the melting crucible 8 with a predetermined diameter. The coil 9 is covered with a coil cement 10, and the coil cement 10 also covers the bottom surface of the melting crucible 8 and is formed into a substantially bottomed cylindrical shape. Coil cement 10
A backup material 11 made of alumina-based powder or the like is filled between the inner circumference and the outer circumference of the melting crucible 8.

In the high frequency induction melting furnace configured as described above, a metal piece is placed in a melting crucible 8 and a coil 9 is energized to melt the metal piece by induction heating. The melted metal piece is supplied to the mold from the gate 12 of the melting crucible 8 by rotating the melting furnace frame 4 by the motor 6.

[0005]

However, in the conventional high frequency induction melting furnace, since the sprue 12 provided in the melting crucible 8 is provided at the upper end surface, the melting furnace frame 4 is tilted to move the mold from the sprue 12 to the mold. When the molten metal is poured into the melting crucible 8, the slag that floats on the upper layer of the melted metal in the melting crucible 8 will first come out. On the other hand, in precision casting, since a casting having a high dimensional accuracy and a good casting surface is required, if slag is mixed in the casting, it becomes a defective product. Various methods have been conventionally devised to solve this problem, but all of them have a problem that the cost is increased because the number of working steps is increased and the apparatus is complicated.

The present invention has been made in view of the above circumstances, and it is possible to prevent slag generated in a melting crucible from being mixed into hot water with a simple structure, and to significantly suppress the occurrence of defective products in precision casting. It is an object of the present invention to provide a high frequency induction melting furnace.

In order to achieve the above object, the present invention provides a melting furnace main body having a melting crucible around which a coil is wound, and a melting furnace frame rotatably mounted on a pedestal to support the melting furnace main body. In a high frequency induction melting furnace equipped with,
A molten metal is tapped in the vicinity of a connecting part of the melting crucible, which has a semicircular cross-section facing the upper end surface of the melting crucible and one end of which is connected to the outer periphery of the melting crucible. It is characterized in that tap holes are formed.

[0008]

In the high-frequency induction melting furnace having the above structure, the slag floating in the upper layer during the melting of the metal floats above the semi-circular gate by tilting the melting furnace frame, and is positioned below the gate in this state. Only good water comes out of the tap hole. Therefore, it is possible to prevent the slag from being mixed in the hot water discharged to the mold, and it is possible to make a good product.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the high frequency induction melting furnace of the present invention will be described below with reference to the drawings.

1 and 2 show the configuration of an embodiment of the present invention. 1 and 2, parts corresponding to the parts of the conventional example shown in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted as appropriate. The feature of this embodiment resides in the structure of the melting crucible 8, and the configuration of other parts is the same as the conventional example shown in FIG. One end surface of a sprue 21 having a substantially semicircular cross section is integrally fixed to a part of the outer circumference of the open end surface of the melting crucible 8 formed in a substantially bottomed cylindrical shape. 21
Has an outer wall curved in a substantially right-angled direction, and the other end face thereof is parallel to the axial direction of the melting crucible 8. That is, the sprue 21 is in the shape of a container having a wall portion 21 a facing the open end surface of the melting crucible 8. Further, a tap hole 21c is formed in a wall portion 21b near the connection portion of the sprue 21 with the melting crucible 8 in a direction perpendicular to the axial direction of the melting crucible 8. Note that reference numerals 24 and 25 shown in FIG. 2 are wirings for supplying a current to the coil 9, and reference numeral 26 is an input port for inputting a sample into the melting crucible 8.

Next, the operation of this embodiment will be described. A metal piece to be melted is put in the melting crucible 8, and the metal piece is melted by induction heating by energizing the coil 9 with the central axis 8a of the melting crucible 8 being vertical as shown by an arrow A. As a result, the molten metal forms the hot water 22 and the slag 23 floats in the upper layer.

When the hot water 22 is discharged from the melting crucible 8, the melting furnace frame 4 is rotated by about 90 degrees or more by the motor 6 shown in FIG. In this state, the hot water 22 moves toward the sprue 21, and the slag 23 floats above the hot water 22 in the sprue 21. At the same time, only good hot water 22 in which the slag 23 is not mixed is discharged from the hot water discharge hole 21c into a mold (not shown).

According to the present embodiment, a simple structure is provided in which the sprue 21 having a substantially semicircular cross section is provided on the open end surface of the melting crucible 8 and the slag 23 is prevented from being mixed in and only the good hot water 22 is discharged. It is possible to make a good casting product without defects and improve the quality of the product.

The overall structure of the high-frequency induction melting furnace shown in the above embodiment is an example, and may have another structure.

[0015]

As described above, according to the high-frequency induction melting furnace of the present invention, the melting end of the melting crucible is provided with the spout having a semicircular cross section, and the tap hole is formed on the peripheral wall of the spout.
With a simple structure, it is possible to prevent the mixing of slag and to discharge only good water, and it is possible to make good products without defects.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the structure of a melting furnace body provided in an embodiment of a high-frequency induction melting furnace of the present invention.

FIG. 2 is a perspective view of FIG.

FIG. 3 is a front view showing the configuration of an example of a conventional high-frequency induction melting furnace.

[Explanation of symbols]

1 Stand 4 Melting Furnace Frame 5 Melting Furnace Main Body 8 Melting Crucible 9 Coil 21 Gate 21c Hot Spring Hole 22 Melting Metal

Claims (1)

[Claims] 1. A high-frequency induction melting furnace comprising: a melting furnace main body having a melting crucible around which a coil is wound; and a melting furnace frame rotatably mounted on a pedestal and supporting the melting furnace main body. Facing the opening of the upper end surface of the melting crucible, and providing a sprue having a semicircular cross section with one end connected to the outer periphery of the melting crucible, in the vicinity of the connection portion of the sprue with the melting crucible, molten metal A high-frequency induction melting furnace characterized in that tap holes for tapping are formed.