JPH1183336A - Vacuum melting furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum melting furnace which can be manufactured at low cost by simplifying the structure of the furnace and minimizing the same, and for which workability is improved by carrying out the tightening work of tightening bolts from the outside of a vacuum chamber at the time of maintenance. SOLUTION: A vacuum melting furnace has a vacuum chamber housing therein a furnace body, in which a heating coil 5 is wound around an outer circumference of a crucible type melting chamber 4 formed of refractory materials, and a plurality of return magnetic path iron-cores 6 are radially disposed on an outer circumference of the heating coil 5 at an interval from one another. In this vacuum melting furnace, a base end side of each of iron- core tightening bolts 7 for pressing the return magnetic path iron-cores 6 of the furnace body from their outer sides is projected outward from a side wall 11a of a tank 11 of the vacuum chamber and fixed to the side wall with a nut, and each sealed box 18 having a lid mounted airtightly is mounted on the outer wall of the tank in such a manner as to surround the base end side of each iron-core tightening bolt 7 projected outward.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a vacuum melting furnace in which an induction melting furnace is housed in a vacuum chamber, and the furnace is tilted together with the vacuum chamber to discharge the molten metal when the molten metal is discharged.

[0002]

2. Description of the Related Art Generally, melting of an active metal is performed in a vacuum atmosphere or an inert atmosphere such as an argon gas or a nitrogen gas in order to prevent a reaction with a refractory due to oxidation or absorption of hydrogen gas. An induction melting furnace such as a melting furnace is used. The vacuum melting furnace includes a full-vacuum type melting furnace in which the molten metal is poured into the mold in a vacuum chamber, and a simple vacuum melting furnace in which the molten metal is poured in the atmosphere.

In the structure of this simple vacuum melting furnace, for example, as shown in FIG. 4, a furnace body 2 of an induction melting furnace is housed in a vacuum chamber 1 and the furnace body 2 is tilted together with the vacuum chamber 1. It has a structure for discharging the molten metal 3.
The furnace body 2 of the induction melting furnace spirally winds a heating coil 5 formed of a water-cooled copper tube around an outer periphery of a crucible-shaped melting chamber 4 formed of a refractory material. The return magnetic cores 6 are radially arranged, and the return magnetic cores 6
The base end of the iron core tightening bolts 7 that presses the
And a nut 9.

A vacuum chamber 1 containing a furnace body 2
In the upper part of the tank 11, a vacuum lid 12 is attached so as to be openable and closable on the left and right. Further, on both sides of the vacuum chamber 1, hydraulic cylinders 14, 14 having lower ends rotatably connected to a support frame 13 are provided.
Are connected by a hinge 10 so as to be tilted integrally with the furnace body 2 about a rotation shaft 15 attached to the tip of the vacuum chamber 1 as a center of rotation.

[0005] However, the conventional vacuum melting furnace has a furnace body 2 formed separately in a vacuum chamber 1 surrounded by a furnace frame 8.
Because of the double frame structure that accommodates and integrally mounts, there is a problem that the size of the device is increased, and the auxiliary equipment such as the hydraulic cylinder 14 and the supporting device is also increased, and the device is expensive. Further, in the vacuum melting furnace, the core tightening bolt 7 for tightening the return path core 6 may gradually loosen due to the vibration of the heating coil 5 during use. It is necessary to retighten the bolt 7 again. This retightening must be performed by a worker entering a narrow gap between the tank 11 and the furnace frame 8 or by once pulling the furnace body 2 out of the vacuum chamber 1 and has a problem of poor workability. was there.

[0006]

SUMMARY OF THE INVENTION The present invention eliminates the above-mentioned drawbacks, reduces the size of the apparatus by simplifying the structure, can be manufactured at low cost, and increases the work of tightening the tightening bolts for maintenance in a vacuum chamber. The present invention provides a vacuum melting furnace which can be operated from the outside of the furnace to improve workability.

[0007]

In the vacuum melting furnace according to the first aspect of the present invention, a heating coil is wound around an outer periphery of a crucible-shaped melting chamber formed of a refractory material, and a plurality of the coils are spaced around the outer periphery. In a vacuum melting furnace in which a furnace body in which return magnet cores are radially arranged is housed in a vacuum chamber, the base end side of a core tightening bolt for pressing the return magnet core of the furnace body from the outside is attached to the vacuum chamber. The seal box, which is projected from the tank side wall to the outside and fixed to the tank side wall with a nut, and the lid is confidentially attached, is attached to the tank outer wall so as to surround the base end side of the iron core tightening bolt projecting to the outside. It is characterized by the following.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is shown in FIG.
This will be described in detail with reference to FIG. As shown in FIG. 1, the upper part of the vacuum chamber 1 is supported by a rotating shaft 15 mounted on the upper part of a support frame 13, and the lower ends of both sides of the vacuum chamber 1 are rotatable by the hinge 10 at the lower end of the support frame 13. Are connected by a hinge 10 provided on the upper part of hydraulic cylinders 14 and 14 connected to the
And tilts together.

The vacuum chamber 1 comprises a tank 11 and a vacuum lid 12 mounted on the tank 11 so as to be openable and closable.
The furnace body 2 of the induction melting furnace is housed inside 11. As shown in FIG. 2, the furnace body 2 is provided with a support 17 made of a refractory and heat-insulating material at the bottom of a tank 11, and a crucible-shaped melting chamber 4 made of a refractory material is formed thereon. I have. A heating coil 5 formed of a water-cooled copper tube is spirally wound around the outer periphery of the crucible-shaped melting chamber 4, and a plurality of return magnetic path cores 6 are spaced apart from the outer periphery of the heating coil 5. Are arranged radially so as to be pressed from the outside.

Further, iron core tightening bolts 7 for pressing and supporting the return path iron core 6 from the outside penetrate the side wall of the tank 11 of the vacuum chamber 1 as shown in FIG. ing. A cylindrical seal box 18 is attached to the outer wall so as to surround the base end protruding outward from the side wall 11a of the iron core tightening bolt 7. This seal box
A disk-shaped lid 21 is attached to a flange 19 provided at an opening of the opening 18 with a bolt 22 and a nut 9 via a packing 20,
The inside of the seal box 18 is kept confidential.

In the vacuum melting furnace having the above structure, as shown in FIG. 2, the vacuum lid 12 is removed, the material is charged into the crucible-shaped melting chamber 4, the vacuum lid 12 is closed, and the inside is a vacuum pump (not shown). A high-frequency current is supplied to the heating coil 5 while the material is being evacuated, thereby inductively heating the material. Material melts and molten metal 3
When the vacuum lid 12 shown in FIG. 1 is opened and the hydraulic cylinders 14 and 14 are operated, the cylinder extends and the vacuum chamber 1 rises and tilts about the rotating shaft 15 together with the furnace body 2. Then, the molten metal 3 is discharged from the gate 16 into the mold.

Therefore, in the vacuum melting furnace having the above-described structure, the furnace frame is eliminated, and the core fastening bolt 7 is provided in the tank 11 of the vacuum chamber 1.
Is directly attached, and the side wall 11a of the tank 11 has a structure that also serves as a furnace frame.
As a result, auxiliary equipment such as the hydraulic cylinder 14 and the supporting device can be downsized, and the device can be manufactured at low cost.

Further, during use, the core tightening bolt 7 for tightening the return path core 6 is loosened by the vibration of the heating coil 5, so that during maintenance, the seal box 18 attached to the outer wall of the tank 11 is used. By removing the lid 21 and rotating the nut 9 attached to the base end of the core fastening bolt 7 inside, retightening can be performed. As a result, it is not necessary for an operator to enter a narrow gap between the tank 11 and the furnace frame 8 as in the related art, and it is not necessary to pull out the furnace body 2 from the vacuum chamber to perform the operation. it can.

In the above description, the case where the inside of the vacuum chamber 1 is evacuated for melting is shown, but the same applies to the case where an inert gas such as an argon gas or a nitrogen gas is sealed and dissolved.

[0015]

As described above, according to the vacuum melting furnace of the present invention, the core fastening bolt is projected from the tank side wall of the vacuum chamber to the outside and fixed, and the tank side wall supports the furnace frame supporting the furnace body. Since the base end side of this protruding iron core tightening bolt is sealed with a seal box,
The structure is simplified, the size of the device can be reduced, and the device can be manufactured at low cost. In addition, when maintenance is performed, the lid of the seal box can be opened, and the work of retightening the iron core tightening bolt can be performed from the outside, so that the workability can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a side view of a vacuum melting furnace according to an embodiment of the present invention.

FIG. 2 is a partially cutaway front view of the vacuum melting furnace shown in FIG.

FIG. 3 is an enlarged sectional view showing a mounting portion of a fastening bolt of the vacuum melting furnace of FIG. 2;

FIG. 4 is a side view showing a conventional vacuum melting furnace with a part cut away.

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Furnace body 3 Metal melt 4 Crucible-shaped melting chamber 5 Heating coil 6 Return path core 7 Iron core tightening bolt 8 Furnace frame 9 Nut 11 Tank 12 Vacuum lid 14 Hydraulic cylinder 17 Support base 18 Seal box 21 Lid

Claims (1)

[Claims] 1. A furnace body in which a heating coil is wound around the outer periphery of a crucible-shaped melting chamber made of a refractory material, and a plurality of return magnetic cores are radially arranged around the outer periphery of the heating coil in a vacuum chamber. In the vacuum melting furnace housed in, the base end side of the core tightening bolt for pressing the return magnetic core of the furnace body from the outside is projected outward from the tank side wall of the vacuum chamber and fixed to the tank side wall with a nut, A vacuum melting furnace, wherein a seal box having a cover attached secretly is attached to an outer wall of a tank so as to surround a base end side of the iron core fastening bolt protruding outside.