JP2004160507A - Direct casting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a direct casting apparatus which reduces the possibility of oxidation and can extend the service life of a metallic mold etc. <P>SOLUTION: This direct casting apparatus is provided with: a melting furnace 10 for melting metal; a control rod 11 for controlling the discharging quantity of molten metal from the above melting furnace 10; an inclined cooling plate 12 for cooling the molten metal discharged from the melting furnace 10; and a casting mechanism for casting the molten metal cooled to a prescribed temperature on the inclined cooling plate 12. Since the metal melted in the above melting furnace is directly cast, the possibility of the oxidation is reduced and the service life of the metallic mold etc., can be extended. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a direct casting apparatus that effectively utilizes the rheology of a semi-molten and semi-solid metal.
[0002]
[Prior art]
In general, as a casting method utilizing the rheology and thixotropy of semi-solid / semi-solid metal, that is, the property of having low viscosity and excellent fluidity, rheocasting method (semi-solidification casting method) and thixocasting method (semi-solid casting method) All of these casting methods are known in which casting is performed using a semi-molten and semi-solidified metal slurry in which a molten liquid phase metal and a solid phase metal are mixed.
[0003]
The above-mentioned conventional rheocasting method is a casting method in which a solid metal is once completely melted, cooled to a metal slurry in a semi-solid state in which granular crystals are generated, and then supplied to a mold.
In addition, the thixocasting method is a casting method in which a solid metal once produced by a rheocasting method is heated until it becomes a metal slurry in a semi-molten state and then supplied to a mold. This is a casting method in which a solid metal is heated to a semi-molten metal slurry and then injected into a mold.
[0004]
[Problems to be solved by the invention]
However, in the direct casting method using the above thixotropic method, it is necessary to have as fine and uniform non-dendritic crystals as possible, preferably spherical crystals. However, simply heating a solid metal to a semi-molten state or simply cooling a molten metal to a semi-solid state will result in most of them becoming dendrites and appearing in the semi-molten / semi-solid metal. The thixotropy of the molten metal and the rheological fluidity of the semi-solid metal cannot be sufficiently obtained.
[0005]
Therefore, in the thixomolding method using thixotropy, an injection molding machine is generally used, and a shear force is applied to the chip-shaped or pellet-shaped solid metal in the barrel of the extruder using a screw-type extrusion mechanism. A method has been used in which a metal slurry in a semi-molten state is sequentially heated while being applied to give a metal slurry in a semi-molten state.
[0006]
However, the screw type extrusion mechanism has a drawback that the construction cost of the casting equipment is extremely enormous due to its complicated structure and high cost.
Further, in the above-mentioned casting method, heat is wasted because the ingot is once cut into chips or pellets, and the resulting material is reheated and semi-melted before casting.
[0007]
The present invention has been proposed in view of the above circumstances, and provides a direct casting apparatus that does not require remelting of a raw material metal, and that can shorten a finishing step and improve strength by pouring molten metal of a spheroidized crystal. The purpose is to do.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 is a melting furnace for melting a metal, a control rod for controlling a discharge amount of the molten metal from the melting furnace, and a molten metal discharged from the melting furnace. And a casting mechanism for casting a semi-molten / semi-solidified molten metal cooled to a predetermined temperature by the inclined cooling plate, wherein the molten metal is directly cast in the melting furnace. .
[0009]
In the invention according to claim 2, a holding furnace for promoting spheroidization of crystals in the molten metal cooled to a predetermined temperature by the inclined cooling plate is provided, and the molten metal is directly cast from the holding furnace. It is characterized by.
[0010]
Further, in the invention according to claim 3, the casting mechanism is a forging press.
[0011]
Further, in the invention described in claim 4, the casting mechanism is a cold chamber die casting.
[0012]
Further, in the invention according to claim 5, the molten metal is a Mg alloy.
[0013]
The invention according to claim 6 is characterized in that the forging press performs casting at a temperature in a semi-molten / semi-solidified state of the Mg alloy.
[0014]
In the invention according to claim 7, the control rod is capable of discharging 70 to 80% of the molten metal in the melting furnace.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings showing one embodiment. FIG. 1 is an explanatory diagram showing one embodiment of a direct casting apparatus according to the present invention. Here, the direct casting apparatus includes a melting furnace 10 for melting the metal, a control rod 11 for controlling a discharge amount of the molten metal from the melting furnace 10, and an inclined cooling for cooling the molten metal discharged from the melting furnace 10. A plate 12, a holding furnace 13 for promoting the spheroidization of the molten metal cooled to a predetermined temperature by the inclined cooling plate 12, and a forging press 14, which is a type of a casting mechanism for casting the held molten metal, are provided. .
[0016]
The melting furnace 10 has a heater 15 around it and a melting tank 16 for melting metal. The melting tank 16 has a discharge pipe 17 for discharging the molten metal, and a control rod 11 that can move up and down into the melting tank 16. The discharge pipe 17 has a lower end 17 a projecting from the outer bottom of the melting furnace 10 and opening above the inclined cooling plate 12, and an upper end 17 b opening at a position lower than the wall surface 16 a of the melting tank inside the melting tank 16. I have.
[0017]
The control rod 11 is made of a heat-resistant material, and is disposed so as to be able to move up and down by a drive mechanism (not shown). With the lowering of the control rod 11, the upper surface of the molten metal in the melting tank 16 rises and overflows from the upper end 17b of the discharge pipe 17. The amount of the molten metal discharged from the discharge pipe 17 can be controlled by the descending amount of the control rod 11.
[0018]
The inclined cooling plate 12 is inclined at a predetermined angle, is provided with a cooling pipe 18 on the lower surface, and cools the flowing molten metal. The molten metal flows on the inclined cooling plate 12 for about 10 to 50 seconds, and then flows down into the holding furnace 13. The holding furnace 13 is provided with a heater 19 around it and has a space 13 a for accommodating the ladle 20.
[0019]
The forging press 14 has an uneven mold, and can be forged into a desired shape by moving up and down by a driving mechanism (not shown).
[0020]
Next, the operation of the direct casting apparatus configured as described above will be described. First, a metal, for example, a magnesium (Mg) alloy is melted in the melting furnace 10. The molten metal is discharged from the discharge pipe 17 by operating the control rod 11. The vertical movement of the control rod 11 can be accurately controlled by controlling the electric motor via a gear with a computer. In addition, since magnesium alloy has the lightest specific gravity among practical metals, most of the impurities are accumulated at the bottom of the melting tank 16 in the melting furnace 10, and the impurities can be easily removed if only the molten metal supernatant is taken out. can do.
[0021]
The impurities accumulated at the bottom of the melting tank 16 are called dross, and when this dross is mixed into the product, it becomes a defective product instead of a clean magnesium alloy. Therefore, it is desirable that the amount of the molten metal in the melting tank 16 that can be discharged by lowering the control rod 11 is 70% to 80% of the melting tank 16. Impurities (dross) such as oxides and iron accumulated at the bottom of the melting tank 16 are discharged from the dross vent 21 as appropriate. Magnesium alloy melts at about 600 ° C., but dross does not melt unless it is at about 1000 ° C., so it is treated using a heat source other than the melting furnace 10.
[0022]
The molten metal discharged from the discharge pipe 17 flows on the inclined cooling plate 12, is cooled, and then flows down into the holding furnace 13. The holding furnace 13 is held in a solid-liquid coexistence state by a surrounding heater 19 and promotes the growth of spheroidized crystals of the molten metal. After being held in the holding furnace 13 for about 30 minutes, it is carried to the forging press 14 by the ladle 20 and cast. The casting temperature is between 570 ° C. + 15 ° C. and −5 ° C. When casting is performed at such a temperature, the heat resistance temperature of the mold and the machine is also about 600 ° C., so that the service life of the mold and the casting machine can be greatly extended. Further, since casting and forging are performed in the state of the spheroidized crystal, a beautiful finish can be obtained, and the finishing process can be greatly reduced, and the strength of the product can be improved.
[0023]
Further, since the product is directly cast without manufacturing the metal ingot, the time and heat energy for re-melting the ingot for 30 minutes or more at 620 ° C. can be saved. Furthermore, since only the molten metal supernatant water is used, a good product containing no impurities can be obtained. Therefore, the product yield can be improved.
[0024]
FIG. 2 is an explanatory view showing a second embodiment of the direct casting apparatus according to the present invention. In the present embodiment, the molten metal held in the holding furnace 13 is transferred from the ladle 20 to the cold chamber die casting 22 for casting. A molten metal is poured from a sprue 23 of a cold chamber die casting 22 and injected into a mold 26 by a plunger 25 driven by a piston 24.
[0025]
Also in the case of the above configuration, only the supernatant liquid of the molten metal can be cast, so that the product yield can be improved. In addition, a spheroidized crystal of a semi-molten / semi-solidified magnesium alloy can be cast as it is, and the strength of the product can be improved.
[0026]
FIG. 3 is an explanatory view showing a third embodiment of the direct casting apparatus of the present invention. In the present embodiment, the molten metal flowing on the inclined cooling plate 12 and cooled is directly injected into the gate 23 of the cold chamber die casting 22.
[0027]
In the case of the above configuration, the holding furnace 13 can be omitted, so that the configuration can be simplified.
[0028]
FIG. 4 is an explanatory view showing a fourth embodiment of the direct casting apparatus of the present invention. In the present embodiment, the direct casting apparatus includes an electric furnace 30 for melting metal, a heat-resistant control rod 31 for controlling the amount of molten metal discharged from the electric furnace 30, and a molten metal discharged from the electric furnace 30. A cooling plate 32 for cooling the molten metal, a tundish 33 for storing the molten metal cooled to a predetermined temperature by the inclined cooling plate 32, and a continuous casting machine 34 for casting the stored molten metal.
[0029]
The electric furnace 30 has a heater 35 via a heat insulating material 30a, and a heat-resistant control rod 31 is provided so as to be able to descend. The heat-resistant control rod 31 is driven down by a drive mechanism 36 outside the furnace. Further, the electric furnace 30 has a discharge path 38 having a heater 37 around it. The discharge path 38 is mounted near the upper end of the electric furnace 30 and is surrounded by a heat insulating material.
[0030]
The inclined cooling plate 32 is inclined at a predetermined angle, is provided with a cooling pipe 39 on the lower surface, and cools the flowing molten metal. After flowing over the inclined cooling plate 32 for about 10 to 50 seconds, the molten metal flows down into the tundesh 33. The molten metal guided from the tundesh 33 to the continuous casting machine 34 is cast here.
[0031]
As described above, according to the present embodiment, only the supernatant liquid of the molten metal is discharged, so that there is no possibility that impurities are mixed into the cast product. Therefore, the product yield can be improved. In addition, since the casting is a spheroidized crystal metal in which a liquid and a solid are mixed, the strength of the product is improved and the finishing step is shortened.
[0032]
FIG. 5 is an explanatory view showing a fifth embodiment of the direct casting apparatus of the present invention. In the present embodiment, the direct casting apparatus includes a melting tank 16 for melting the metal, a control rod 11 for controlling the amount of the molten metal discharged from the melting tank 16, and a molten metal discharged from the melting tank 16. Left and right two hot water supply pipes 40a, 40b, an inclined cooling plate 32 for cooling the molten metal, and an insulated container 41 for storing the semi-solidified / semi-solidified molten metal cooled to a predetermined temperature by the inclined cooling plate 32. Have.
[0033]
The hot water supply pipe 40 has a heater 37 around it to prevent the molten metal from being rapidly cooled. Further, similarly to the above-described embodiment, the inclined cooling plate 32 is inclined at a predetermined angle, is provided with a cooling pipe 39 on the lower surface, and cools the molten metal flowing down.
[0034]
As described above, according to the present embodiment, the molten metal is simultaneously supplied to a plurality of locations, so that casting can be performed efficiently. Therefore, the product yield can be improved. Further, the molten metal can be supplied from one melting tank 16 to a plurality of devices such as a high-pressure casting machine, a press or a casting machine, and the working efficiency can be improved.
[0035]
In the above embodiment, the case where the number of hot water supply pipes is two has been described.
[0036]
【The invention's effect】
Since the present invention has the above-described configuration, the following effects can be obtained.
[0037]
In the invention according to claim 1, a melting furnace for melting the metal, a control rod for controlling a discharge amount of the molten metal from the melting furnace, and an inclined cooling plate for cooling the molten metal discharged from the melting furnace, A casting mechanism for casting the semi-molten / semi-solidified molten metal cooled to a predetermined temperature by the inclined cooling plate is provided.Since the molten metal is directly cast in the melting furnace, the step of re-melting is reduced, thereby saving energy. realizable. Therefore, the manufacturing cost can be reduced. Further, since the molten metal flows directly down the inclined cooling plate, there is little chance of contact with air, so that the oxidation reaction is reduced and the yield rate is improved.
[0038]
In the invention according to claim 2, a holding furnace for promoting spheroidization of crystals in the molten metal cooled to a predetermined temperature by the inclined cooling plate is provided, and the molten metal is directly cast from the holding furnace. The molten metal of the spheroidized crystal can be cast, and the finishing step can be shortened. Further, the strength of the product can be improved.
[0039]
Further, in the invention according to claim 3, since the casting mechanism is a forging press, it is possible to forge a material that cannot be processed at room temperature or a product having a complicated shape.
[0040]
Further, in the invention described in claim 4, since the casting mechanism is a cold chamber die casting, a conventional cold chamber die casting machine can be used as it is. Further, shortening of the finishing step can be realized.
[0041]
Further, in the invention described in claim 5, since the molten metal is an Mg alloy, the Mg alloy can be cast as spherical crystals, and the finishing step can be shortened.
[0042]
Further, in the invention according to claim 6, since the forging press casts at a temperature in a semi-molten and semi-solid state of the Mg alloy, the service life of the mold and the casting apparatus can be extended. That is, since the battery is used at a temperature equal to or lower than the yield point of the mold and the casting apparatus, the service life can be greatly extended.
[0043]
Further, in the invention according to claim 7, since the control rod can discharge 70 to 80% of the molten metal in the melting furnace, the discharge of the molten metal in the melting furnace can be easily controlled. Further, since the control rod can take out only the supernatant portion of the molten metal, impurities having a high specific gravity can be accumulated in the bottom portion of the melting furnace.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing an embodiment of a direct casting apparatus according to the present invention.
FIG. 2 is an explanatory view showing a second embodiment of the direct casting apparatus.
FIG. 3 is an explanatory view showing a third embodiment of the direct casting apparatus.
FIG. 4 is an explanatory view showing a fourth embodiment of the direct casting apparatus.
FIG. 5 is an explanatory view showing a fifth embodiment of the direct casting apparatus.
[Explanation of symbols]
REFERENCE SIGNS LIST 10 melting furnace 11 control rod 12 inclined cooling plate 13 holding furnace 14 forging press 15 heater 16 melting tank 17 discharge pipe 18 cooling pipe 19 heater 20 ladle 21 dross removal 22 cold chamber die casting 23 gate 24 piston 25 plunger 26 mold 30 Electric furnace 31 Heat-resistant control rod 32 Inclined cooling plate 33 Tundesh 34 Continuous casting machine 36 Drive mechanism 38 Discharge path

Claims (7)

A melting furnace for melting the metal,
A control rod for controlling the amount of molten metal discharged from the melting furnace,
An inclined cooling plate for cooling the molten metal discharged from the melting furnace,
A casting mechanism for casting a semi-molten and semi-solid metal cooled to a predetermined temperature by the inclined cooling plate,
A direct casting apparatus, wherein the metal melted in the melting furnace is directly cast. The direct heating according to claim 1, further comprising a holding furnace for promoting spheroidization of crystals in the molten metal cooled to a predetermined temperature by the inclined cooling plate, and directly casting the molten metal from the holding furnace. Casting equipment. The said casting mechanism is a forging press, The direct casting apparatus of Claim 1 or 2 characterized by the above-mentioned. The said casting mechanism is a cold chamber die casting, The direct casting apparatus of any one of Claims 1-3 characterized by the above-mentioned. The said molten metal is Mg alloy, The direct casting apparatus of any one of Claims 1-4 characterized by the above-mentioned. The direct casting apparatus according to any one of claims 1 to 5, wherein the forging press performs casting at a temperature in a semi-molten and semi-solid state of the Mg alloy. The direct casting apparatus according to any one of claims 1 to 6, wherein the control rod is capable of discharging 70 to 80% of molten metal in a melting furnace.

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