JP2872863B2 - Method for producing billet for thixocast - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a billet used for thixocast casting, in which a semi-molten metal is pressed in a mold cavity and molded.

[0002]

2. Description of the Related Art When heated to a semi-molten state, such a billet preferably has a non-dendritic, spherical metal structure as fine and uniform as possible. For this purpose, it is known that the molten metal may be agitated by any method during the production of the billet. However, whether using conventional mechanical stirring, electromagnetic stirring, or vibration stirring,
In spite of the large scale of the apparatus, there was a problem that a uniform and fine metal structure could not be obtained.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of such conventional problems, and a billet having a uniform and fine metal structure can be manufactured with a relatively simple apparatus. It is intended to provide a method for producing a thixocast billet.

[0004]

According to the method for producing a thixocast billet of the present invention which achieves the above object, after absorbing an inert gas into a molten metal, the inert gas dissolved in the molten metal is removed. It is characterized by being rapidly released in a vacuum chamber and then formed into a column while cooling.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the schematic diagram of FIG.

The molten metal 1 is made of aluminum, its alloy, etc.
An inert gas 3 such as nitrogen is absorbed and dissolved therein in a gas pressurizing chamber 2 by using a billet conventionally used for producing this kind of billet. At this time, as a matter of course, pressure is applied to the inert gas 3 so that as much of the inert gas 3 as possible is absorbed and dissolved in the molten metal 1.

[0007] Next, the flow stopper 5 for communicating the gas pressurizing chamber 2 and the vacuum chamber 4 is opened, and the molten metal 1 containing a large amount of the inert gas 3 is poured into the vacuum chamber 4. Then, the inert gas 3 dissolved in the molten metal 1 is rapidly released from the degasser 6 in the vacuum chamber 4, and the molten metal 1 is vigorously stirred by a bubbling phenomenon at that time. As a result, the metal structure of the molten metal 1 becomes a fine and uniform non-dendritic and spherical metal structure.

After that, the molten metal 1 is formed into a rod-shaped column through the continuous mold 7, and is cooled and solidified as it is in the cooling unit 8 to form the billet 9. The inert gas and the like in the vacuum chamber 4 are exhausted to the outside through the exhaust holes 10.

In the illustrated embodiment, the billet 9 is continuously manufactured using the continuous mold 7, but the mold is set in the vacuum chamber 4 and the billet 9 is batch-processed. It may be manufactured.

[0010]

According to the method for producing a billet for thixocasting of the present invention, the inert gas dissolved in the molten metal is rapidly released in the vacuum chamber, and the bubbling phenomenon at that time causes the molten metal to be melted. As a result of the vigorous stirring, a billet having a uniform, fine, non-dendritic, spherical metal structure can be produced with a relatively simple apparatus.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an embodiment of the present invention.

[Explanation of symbols]

 1: Molten metal 2: Gas pressurization chamber 3: Inert gas 4: Vacuum chamber 5: Flow plug 6: Degassing part 7: Continuous mold 8: Cooling part

Claims (1)

(57) [Claims] 1. A method in which an inert gas dissolved in a molten metal is rapidly released in a vacuum chamber after absorbing the inert gas into the molten metal, and then formed into a rod-like column while cooling. A method for producing a billet for thixocast, comprising: