JP2005199344A - Suction casting method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a suction casting method by which contamination and heat loss caused by a crucible is prevented, molten metal is filled into a mold vigorously to be run satisfactorily, and also the occurrence of a defect caused by the inclusion of gas is prevented. <P>SOLUTION: A pipe-shaped metal to be melted is fitted to the sprue of the mold, the inside of the mold are evacuated and held in an almost vacuum state. In the state, the pipe-shaped metal to be melted fitted to the sprue of the mold is heated and melted and brought into a state wherein the drops of the molten metal are sucked on the sprue of the mold by the viscosity and surface tension of the metal. Pressure inside a sealed vessel is rapidly increased, and, by the pressure difference between the inside of the mold and the inside of the sealed vessel, the molten metal is sucked inside the mold. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a suction casting method and an apparatus therefor.

In the conventional suction casting method, a negative pressure is introduced into the mold, and the molten metal is sucked into the mold and cast by a pressure difference between the inside and outside of the mold.

In the case of the conventional suction casting method, casting is performed in a state where gas is present inside the mold, and this may cause gas entrainment and a poor product state.
Also, most of the molten metal is heated in the crucible, so heat loss and contamination by the crucible, and crucible breakage may occur in metals with a high melting point temperature.

Further, in the conventional suction casting method, since the mold needs to have air permeability, the product surface condition tends to become rough.

The invention of the present application has been made to solve such problems. Thus, the first invention of the present application relates to a suction casting method, in which a metal to be melted in a pipe shape is attached to a pouring gate of the mold, and the mold and the inside of the mold are substantially sucked and held in a vacuum state. The pipe-like metal to be melted attached to the mold gate is heated and melted so that the molten metal in the form of drops is adsorbed to the mold gate by the viscosity and surface tension of the metal, and the pressure inside the sealed container is reduced. The molten metal is sucked into the mold by a pressure difference between the mold and the sealed container. (Claim 1)

Further, another invention of the present application relates to a suction casting apparatus. (A) A mold in which a pipe-like metal to be melted is attached to a gate and (b) the pipe in the sealed container is heated and dissolved so that the viscosity and surface of the metal From the state in which the spherical molten metal is adsorbed to the pouring gate of the mold by tension, the pressure in the sealed container is rapidly increased to suck the molten metal into the mold. (Claim 2)

As described above, according to the first aspect of the present invention, the molten metal can be brought into a state where the molten metal in the form of droplets is adsorbed to the gate of the mold by the viscosity and surface tension of the metal.

Therefore, in this method, since the metal is melted without using a crucible, heat loss and contamination by the crucible can be prevented, and even a metal having a high melting temperature can be melted uniformly.

Thus, in this method, from the state in which the molten metal is adsorbed to the pouring gate of the mold, the pressure inside the sealed container is rapidly increased to cause the molten metal to enter the mold by the pressure difference between the mold interior and the sealed container. By sucking, the molten metal is sucked vigorously and filled into the mold.

Accordingly, the molten metal around the thin portion is sufficient. Further, in the present invention, since casting into the mold is performed under a substantially vacuum state, there is no risk of gas being entrained when the molten metal is vigorously injected, and casting defects due to gas entrainment are not caused.

Thus, in this method, it is not necessary to give the mold air permeability, and a product having a good surface state can be obtained.

The apparatus according to claim 2, wherein a mold in which a pipe-shaped metal to be melted is attached to a gate and the pipe in the sealed container is heated and melted, and the molten metal in a drop shape is formed by the viscosity and surface tension of the metal. From the state of adsorbing to the pouring gate, the pressure in the sealed container can be rapidly increased to suck the molten metal into the mold vigorously.

According to the apparatus of the present invention, the method of claim 1 can be carried out satisfactorily, and a product having a good surface condition can be obtained by sufficiently filling even a thin part without gas entrainment.

Next, embodiments of the present invention will be described in detail with reference to the drawings. In FIG. 1, reference numeral 2 denotes a chamber, which is effectively kept in a vacuum by a vacuum pump 7, and 4 is a metal to be melted, which is processed into a pipe shape and attached to the mold 1.

From this state, the metal 4 to be melted is induction-heated and melted by the high-frequency induction heating coil 3 from the outside of the pipe 5. At this time, as shown in FIG. 2, the molten metal becomes a drop-like lump due to viscosity and surface tension and is adsorbed on the tip of the metal to be melted in a pipe shape.

The high frequency induction heating coil 3 is moved upward while heating to such an extent that the viscosity of the molten metal is not lost, and all the metal 4 to be melted as shown in FIG. 3 is dissolved. At this time, in order to prevent the molten metal from falling due to its own weight, an inert gas such as argon gas is slightly sent into the chamber, the pressure in the chamber is slightly increased, and the molten metal is sucked into the mold by the pressure difference from the inside of the mold in a vacuum state. Try to stick.

Further, just before the molten metal is heated and loses its viscosity and falls, an inert gas such as high-pressure argon gas is sent into the chamber, so that the pressure difference between the inside of the vacuum mold and the high-pressure chamber is as shown in FIG. Molten metal is filled into the mold.

It is a figure of the casting apparatus which is one Example of this invention. It is the figure in the middle of casting and the casting apparatus which is one Example of this invention. It is the figure in the middle of casting and the casting apparatus which is one Example of this invention. It is the figure at the time of completion | finish of casting and the casting apparatus which is one Example of this invention.

Explanation of symbols

1 Mold 2 Chamber 3 High-frequency induction heating coil 4 Melting metal (pipe shape)
5 Pipe made of glass, copper, or material less affected by induction heating 6 Switching valve 7 Vacuum pump 8 Inert gas tank (argon gas, etc.)

Claims (2)

In a suction casting method in which a molten metal is sucked into the mold while the inside of the closed container and the inside of the closed container is decompressed and the mold is sucked into the mold, a pipe-shaped metal to be melted is attached to the pouring gate of the mold. In this state, the pipe-shaped metal attached to the mold gate is heated and melted, and the molten metal in the form of droplets enters the mold gate due to the viscosity and surface tension of the metal. A suction casting method characterized in that the molten metal is sucked into the mold due to a pressure difference between the inside of the mold and the hermetic container by rapidly increasing the pressure inside the hermetic container and adsorbing it. (B) A mold in which a metal to be melted in a pipe shape is attached to the gate, and (b) the pipe in the sealed container is heated and melted, and the molten metal in the form of drops due to the viscosity and surface tension of the metal. A suction casting apparatus characterized in that, from the adsorbed state, the pressure in the sealed container is rapidly increased to suck the molten metal into the mold.

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