JP2002011561A - Method and apparatus for producing light metal castings, especially parts made of magnesium or magnesium alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a practical and high-performance method for producing a light metal cast article and a method which can be realized by a simpler technique than required by a conventional method. , And an apparatus for performing the method. SOLUTION: Heating of the liquid metal is performed in a lower part of a melting device adjacent to a gate system, and the liquid metal is heated to a temperature of about 630 ° from a mold side to a lower part of a valve seat in an airtight closed system to the outside. This is achieved by a manufacturing method in which C is changed from a molten state to a solidified state, and the supply and recovery of protective gas are performed by a differential pressure system. As an apparatus for carrying out this method, a metal pipe which supplies liquid metal from a pre-melting furnace 16 via a check valve 17 and is hermetically provided to the outside is arranged in the vessel 1 of the melting apparatus. . A differential pressure system 9 is connected to the vessel of the melting apparatus for supplying and recovering the protective gas, and an airtight gate device is provided in the vessel of the melting apparatus to supply the solid raw material metal.

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 light metal castings, in particular magnesium and magnesium alloy parts, and to an apparatus for carrying out the method.

[0002]

2. Description of the Related Art A method and an apparatus for producing a pressed product, in particular a magnesium pressed product, is known from DE-OS 44 31 865. In this method, liquid metal is introduced into a measuring chamber, a pressurized gas is introduced, and the liquid metal is pressed into a pre-evacuated mold by the action. This method and the apparatus for carrying it out have the disadvantage that the compression ratio of the gas used in the fabrication of the prototype is not compatible with mass production. Further, in this apparatus, the relationship between the temperature of the mold and the molten crucible is not preferable in practice, and the required temperature difference between the molten crucible and the pouring portion is extremely large. It is possible, in particular overheating of the sealing element. The open container described in DE-OS 44 31 865 cannot be used from the production of prototypes of light metal parts to mass production, especially if argon is used, since a protective gas coating cannot be formed. . Further, it is impossible to add liquid metal required for mass production by this method. The heating element, for example in the form of a cartridge, incorporated in a melting crucible used in DE-OS 44 31 865 does not allow the required solidification of the molten metal.

[0003]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method for producing light metal castings which can be realized by a practical, sophisticated and relatively simple technique, and to carry out the method. Is to provide an apparatus. This object is achieved by the features of claim 1, wherein a preferred embodiment of the method according to the invention is defined by claims 2 to 5
It is described on page 14.

[0004]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention and an apparatus for carrying out the method will be described in more detail with reference to one preferred embodiment. FIG. 1 is a schematic view of the entire system, and shows in principle the structure of a system for manufacturing light metal casting parts which is hermetically sealed against the outside. According to the invention, the metal used for the production of light metal castings, for example magnesium or a magnesium alloy, is heated by a heating element 2 in a pouring retort 1 to about 630 ° C. The shape of the pouring retort 1 is formed so as to be narrowed toward the gate system 4. A heating element 2 is arranged around the pouring retort 1 at the lower part leading to the gate system 4. Due to the shape of the pouring retort 1 and the arrangement of the heating element 2 below it, the temperature relationship required for melting and pouring can be realized.The pouring retort 1 should be formed in a conical shape and placed on the gantry 5. Thereby, it is possible to realize the distance and the heat energy transfer for the solidification of the material. As the heating element 2, a resistance heating element, an infrared heating element, or an induction heating device can be used. Pouring retort 1 having the narrowed shape is placed on gantry 5, and the outlet opening of pouring retort 1 is overlapped with the opening of gantry 5, and closed by valve unit 3. Mount 5
A mold 19 movable in a height direction and a vertical plane and connected to a vacuum device 20 is arranged at a lower portion of the mold. After the exhaust
The valve unit 3 is separated from the opening by the valve control mechanism 12 via the mechanical coupling component 13, and the liquid metal flows into the mold 19. The supply of liquid metal to the pouring retort 1, especially the replenishment necessary for mass production of light metal castings
This is done by a metal conduit 18 from 6. Also check valve 1
7 prevents the backflow of the liquid metal and the disappearance of the pressure difference.
Here, the check valve 17 is connected to the pre-melting furnace 16 together with the metal conduit 18.
The check valve 17 may be placed in the pouring retort 1, or the pouring retort 1 may be placed in the pouring retort 1. There is an advantage that is. The supply of protective gas in the closed system is carried out via a protective gas conduit 8 via a pressure transducer (Drucku
bersetzer) 9. The pressure transducer 9 supplies a protective gas, which is fed back after the production process has been completed. The protective gas line 8 is provided with a control unit for keeping the pressure constant. Protective gas meter in case of pressure drop due to gas leakage from non-hermetic place 1
0, for example compensated by a protective gas cylinder. The valve control mechanism 12 can be formed as a pneumatic type or a hydraulic type. The valve stopper 14 allows the valve unit 3 to be opened in a "pulse-like" manner (for a short time), thereby preventing the formation of holes in the light metal casting.

[0005] The schematic diagram shown in FIG.
This is a modified example. A heating element 2 is provided in a portion narrowed downward of the melting device formed as a pouring retort 1. The outlet of the pouring retort 1 toward the mold 19 is closed by the valve unit 3. Exhaust device 20
After the evacuation is completed, the valve unit 3 opens in a short time by the valve control mechanism 12 and the valve stopper 14, and the metal flows into the mold 19. Due to metal loss in the pouring retort 1, several times the amount of metal is required when preparing metal for each part to be cast.
After the liquid metal has been supplied to the sprue system 4, the solidification process proceeds by removal of thermal energy by the gantry 5 and by the mold 19 being automatically separated from the sprue system 4. Pouring retort 1 is inside the pouring unit and is surrounded by insulation 6. The temperature of the melt is measured by the temperature sensor 7, and a signal corresponding thereto is transmitted to the valve control mechanism 12.

FIG. 3 shows a second modification of the embodiment of the mold and the differential pressure system in the apparatus of the present invention.

In this modification, the pouring retort 1
Has a cylindrical shape, and a heating element 2 is disposed below the cylindrical shape. The temperature difference between the sprue system 4 and the mold 19 necessary for solidification is realized by separating the heat insulating material 6 and the mold 19 after pouring the liquid metal. In this variant, the supply of the protective gas is carried out by means of a blower tank 21 which is known per se and a pump system 2 for press-in and suction of the protective gas.
This is done by a differential pressure system consisting of:

[Brief description of the drawings]

FIG. 1 is a schematic diagram of the entire system.

FIG. 2 is a schematic view of a pouring retort which is a first modification of the pouring unit.

FIG. 3 is a schematic view of a mold and a differential pressure system according to a second modification.

[Explanation of symbols]

 1 Pouring retort 2 Heating element 3 Valve unit 4 Gate system 5 Frame 6 Insulation material 7 Temperature sensor 8 Protective gas conduit 9 Pressure transducer 10 Additional protective gas supply device 11 Gate device 12 Valve control mechanism 13 Coupling component 14 Valve stopper 15 Valve Packing 16 Pre-melting furnace 17 Check valve 18 Metal conduit 19 Mold 20 Exhaust device 21 Blower tank 22 Pump system

Claims (14)

[Claims] 1. A method for producing a cast part made of a light metal, in particular, magnesium or a magnesium alloy, in which a liquid metal is introduced into a measuring container, and pressurized gas is injected into the measuring container, whereby the liquid metal is injected into a pre-evacuated mold. So,
It is performed in a closed system that is airtight to the outside, and heats the liquid metal in the lower part of the melting device adjacent to the gate system (4). A method comprising transitioning from a molten state to a solidified state of C and supplying and recovering a protective gas by a differential pressure system. 2. The method according to claim 1, wherein the additional supply of the solid light metal is performed in the closed system through a gate device (11) in which a pressure difference between the outside air and the inside of the melting device is acting. . 3. A metal conduit wherein the supply of light metal is a liquid metal.
Through (18) or as a solid metal gate device (1
The method of claim 1, wherein the method is performed through 1). 4. The method according to claim 1, wherein the quantity of the supplied light metal is several times the quantity of the light metal parts to be produced.
2 and 3 methods. 5. The method according to claim 1, wherein the solidification of the molten light metal is carried out by pulling out a mold device. 6. A pressure transducer for supplying and recovering the protective gas.
(9) and an additional protective gas supply device (10) for compensating for the generated pressure loss.
the method of. 7. The method according to claim 1, wherein the solidification process is carried out by raising the pouring retort (1) and moving it to the side of the mold of the part to be subsequently processed. 8. A pre-melting furnace in a vessel of a melting device.
Supply of liquid metal via a non-return valve (17), placement of an externally gas-tight metal conduit (18), coupling of a differential pressure system to the vessel of the melter, and the melter 2. Apparatus for implementing the method of claim 1, wherein said container is provided with a gate device (11) which is airtight to the outside. 9. Apparatus according to claim 8, wherein said differential pressure system comprises a pressure transducer and an additional supply of protective gas downstream of said pressure transducer to compensate for pressure losses. 10. The system according to claim 1, wherein the differential pressure system is a blower tank.
Device according to claim 8, characterized in that it comprises (21) and a pump system (22) belonging thereto. 11. A metal conduit (18) for supplying liquid metal from a pre-melting furnace (16) via a check valve (17) to a pouring retort (1) which is squeezed towards a gate system (4). )
The pressure transducer (9) is connected to the pouring retort (1), and the protective gas additional supply device (10) for compensating for pressure loss is connected to the pressure transducer (9). ,
A gate device (11) for transporting solid light metal to the pouring retort (1) is installed in an airtight manner, and supply to a valve control mechanism (12) for controlling transport of liquid metal is performed in a very short time. Valve stopper that can be performed
The device of claim 8, comprising (14). 12. A valve stopper, wherein the valve control mechanism is operated by a pneumatic or hydraulic system, and the system is operated by hydraulic, pneumatic or electromagnetic force.
Apparatus according to claim 8, characterized in that it is coupled to (14). 13. The device according to claim 8, wherein the solidification of the liquid metal takes place in a cooled adiabatic channel, and a heat insulating layer (6) is arranged between the melting device and the mold device. 14. A check valve (17) at the lower part of the vessel of the melting device.
Device according to claims 8 and 9, characterized in that it is provided with: