JPH0520673B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a metal melting apparatus for melting active metals.

[Prior Art] Some devices use a water-cooled divided copper crucible as an apparatus for melting active metals (eg, titanium).

FIG. 4 shows a perspective view of the melting device, in which vertically long copper segments 21 are connected in a cylindrical shape via an insulating refractory 22 to form a water-cooled divided copper crucible 23. A high frequency induction heating coil 24 is attached to the outer periphery of the coil. As shown in FIG. 5, a bottom copper water-cooling jacket 33 is inserted into the bottom of this melting device via an insulating refractory 22. In this melting device, when a metal material is placed in a crucible and a high frequency current, for example, 100KHz current is passed through the high frequency induction heating coil 24, the induced current is blocked by the insulating refractory 22 and hardly flows into the copper segments, and inside the crucible. To efficiently melt metal materials such as titanium. The outer periphery and bottom of the molten metal 28 are cooled by the copper segments 21 and the bottom copper water cooling jacket 33 to form a solidified shell 3.
2 to prevent contamination of the molten metal 28 by refractories. After that, alloying elements are added to the melted metal, and the melted metal is placed in the crucible 23 as shown in FIG.
is tilted to pour the molten metal 28 into the lower mold 30 to obtain a casting. At this time, impurity scum (metal oxide consisting of oxides on the surface of the raw metal) floating and separating on the upper surface of the molten metal 28 is brought into the mold 30 below. FIG. 7 shows another conventional example in which the molten metal 28 in the crucible is once placed in a tundish 35 and a stopper 3 is provided at the bottom of the tundish 35.
4 is opened and cast into a mold 30 to obtain a casting.

[Problems to be solved by the invention] However, by tilting the crucible, the molten metal 28 is poured into the mold 3.
In the case of FIGS. 4 to 6, in which the molten metal 28 is cast at zero, there is a problem in that the impurity scum floating and separating on the upper surface of the molten metal 28 is brought into the mold 30 below and becomes a defect in the product casting.

In the case of FIG. 7 in which casting is carried out using a tundish 35 having a stopper 34, impurity scum is not brought into the mold 30, but the molten metal is contaminated by the refractory forming the stopper 34 and the tundish 35, resulting in a product. There is a problem in that it causes defects in the casting.

This invention was made in view of the above circumstances, and is a metal that can prevent impurities from being mixed in and produce castings with fewer defects when melting easily oxidized metals such as titanium and their alloys and casting them into molds. The purpose of the present invention is to provide a dissolving device for this purpose.

[Means for Solving the Problems] The present invention provides a water-cooled divided copper crucible configured by connecting vertically long copper segments in a cylindrical shape via an insulating material, and a water-cooled divided copper crucible configured by connecting longitudinally long copper segments with an insulating material. a nozzle that is connected in a cylindrical shape via a nozzle and is installed in communication with the bottom of the crucible; a high-frequency induction heating coil that is placed on the outer periphery of this nozzle; and a metal that is fitted into the nozzle. This is a metal melting device comprising a stopper.

[Operation] In the present invention, the metal material charged into the crucible is melted by applying electric power to a high frequency induction heating coil provided on the outer periphery. Next, when the molten metal material in the crucible melts, power is applied to a high-frequency heating coil installed on the outer periphery of the nozzle to melt and drop the metal plug, thereby opening the nozzle. The molten metal in the crucible is then poured into the mold.

[Example] A metal melting apparatus of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an example of a metal melting apparatus according to the present invention, and FIG. 2 shows an enlarged view of a nozzle portion. In this device, a crucible 3 has a nozzle 6 attached to its bottom , and high-frequency induction heating coils 4 and 7 are arranged around the outer periphery of the nozzle 6 , respectively. The crucible 3 and the nozzle 6 are constructed by connecting vertically long copper segments 1 in a cylindrical shape via an insulating refractory (not shown). Similarly, the nozzle 6 is constructed by connecting vertically long copper segments 5 through an insulating refractory 2 in a cylindrical shape. A metal plug 9 having the same composition as the target metal is fitted into the nozzle in advance. An example of specific specifications of the metal melting apparatus of the present invention will be given below. The compositions of the melting material 8 and the metal stopper 9 are shown in Table 1 below.

Table 1 Composition of melting material and metal plug Elements Ti Al V Weight % Remaining 6 4 The water-cooled divided copper crucible has an inner diameter of 120 mmφ, a height of 200 mm, and the number of divisions of the water-cooled copper segment 1 is 24. The induction heating coil 4 of the crucible is Inner diameter: 180 mm φ The high frequency power applied to this has a frequency of 100 KHz and an output of 200 KW. The water-cooled divided copper nozzle has an inner diameter of 25 mm φ, the number of divided water-cooled copper segments is 12, and the induction heating coil 7 of the nozzle has an inner diameter of 60 mm.
mmφThe high frequency power supply applied to this has a frequency of 100KHz,
The output is 100KW.

Next, in the melting apparatus configured as described above, the metal in the crucible is melted by the high frequency induction heating coil 4 disposed around the outer periphery of the crucible. Thereafter, as shown in FIG. 3, a high frequency induction heating coil 7 disposed on the outer periphery of the nozzle is energized to heat the metal plug 9 and cause it to melt and fall, thereby injecting the molten metal 8 into the mold 10. In this melting device, the impurity scum falls last, stays in the feeder section 11 of the casting, and does not become an internal defect in the product casting. Further, at the end of casting, the power to the high-frequency induction heating coil 7 on the outer periphery of the nozzle is turned off, so that the nozzle portion is solidified and blocked, and the injection into the mold 10 is stopped. The casting speed is controlled by coil 7.
This is done by adjusting the power input.
Furthermore, when casting a large number of molds, the process of closing and pouring is repeated. After the casting is completed, the metal material that solidifies and closes the nozzle portion is used as a metal plug in the next casting process. In this melting device, when a cylindrical copper crucible is placed inside the high-frequency induction heating coil 4, an annular induced current flows through the wall of the crucible, generating heat and wasting power. However, if the crucible is divided vertically and electrically insulated from each other as described above, this circular current is blocked and heating of the crucible is avoided, so the wasteful power consumption as described above can be avoided. can.

Similarly, the water-cooled divided copper nozzle has the same structure as the water-cooled divided copper crucible, only the size is different.
Therefore, it is possible to similarly reduce power consumption and avoid contamination with impurities when using a refractory nozzle.

Furthermore, since the crucible is composed of water-cooled copper segments, when the metal material charged in the crucible is melted, a part of it forms a solidified shell on the inner wall of the crucible, preventing impurities from entering from the inner wall of the crucible. Similarly, a solidified shell is formed on the inner wall of the nozzle to prevent impurities from entering from the inner wall of the nozzle. The metal stopper preferably has the same composition as the melting material, but is not particularly limited to the same composition.

[Effects of the Invention] The metal melting apparatus of the present invention has a nozzle for inserting molten metal into the crucible at the bottom of the crucible, so that floating and separated impurity scum is not cast into the product casting, thereby causing internal defects in the product casting. There isn't. Further, the nozzle is composed of a water-cooled copper segment, so that there is no contamination of the molten metal by refractories and no internal defects in the product casting. Furthermore, since the injection speed of molten metal can be controlled by adjusting the input of the high frequency power source, it is applicable to the production of large castings as well as the production of many small castings.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of a crucible showing an outline of a metal melting apparatus according to an embodiment of the present invention, and FIG. 2 is a perspective view of a nozzle attached to the bottom of the crucible. FIG. 3 is a conceptual diagram showing a situation in which molten metal is poured into a mold from the crucible. FIG. 4 is a perspective view showing a water-cooled divided copper crucible and a high-frequency induction heating coil arranged around its outer periphery. FIG. 5 is a longitudinal sectional view of the water-cooled divided copper crucible. FIG. 6 is a conceptual diagram showing a situation in which a conventional crucible is tilted and cast. FIG. 7 is a conceptual diagram showing the situation of casting using a tundish. 1...Water-cooled copper segment of the crucible, 2...
Insulating refractory, 3 ... Crucible, 4... High frequency induction heating coil of crucible, 5... Water-cooled copper segment of nozzle, 6 ... Nozzle, 7... High frequency induction heating coil of nozzle, 8... Molten metal , 9... Metal stopper, 10... Mold, 11... Feeder section, 12... Solidification shell, 21... Water-cooled copper segment of crucible, 22... Insulating refractory, 23... Crucible, 2
4... High frequency induction heating coil of crucible, 28...
Molten metal, 30... Mold, 32... Solidified shell,
33...Bottom water-cooled copper jacket, 34...Stopper, 35...Tandish.

Claims (1)

[Claims] 1. A water-cooled divided copper crucible configured by connecting vertically long copper segments in a cylindrical shape via an insulating material, and a water-cooled split copper crucible configured by connecting vertically long copper segments in a cylindrical shape via an insulating material. The crucible is configured as follows: a nozzle installed in communication with the bottom of the crucible, a high-frequency induction heating coil disposed around the outer periphery of the nozzle, and a metal plug fitted into the nozzle. Metal melting equipment. 2. The metal melting apparatus according to claim 1, wherein the metal stopper is made of a metal having the same composition as the metal melted in the crucible.