JP2005081437A - Method for casting aluminum or aluminum alloy - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for casting aluminum or aluminum alloy which can cast molten aluminum or aluminum alloy into a sand mold using green sand, whereby productivity can be remarkably improved. <P>SOLUTION: In the invented method, a sand mold having cavities on the front and rear faces in the direction of a casting line is formed in the forming chamber of a casting line. Then a series of sand molds is formed by piling a plurality of sand molds at the front and rear faces of the casting line. The molten aluminum or aluminum alloy is poured into the cavities from pouring gates provided on the piled faces. The series of sand molds into which the molten aluminum or aluminum alloy has been poured is cut at the middle of the sand mold into every sand mold or every plurality of sand molds, and is cooled by immersing them into water. Then, the sand molds are scrapped, and the sand after the scrapping is dried and supplied into the forming chamber for recycling. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a casting method of aluminum or aluminum alloy castings such as aluminum wheels for automobiles.

  Conventionally, castings made of aluminum or aluminum alloy such as so-called aluminum wheels are manufactured by a casting method using a mold such as a mold casting method. On the other hand, in the case of cast iron, a casting method using a mold (sand mold) formed from green sand is also employed. This is because, in the case of cast iron, there is no problem in casting quality even if the cooling rate is slow, and in the case of cast iron, the molten metal temperature is high, which makes it difficult to use a mold. is there.

  Under such background technology, a casting method using a fresh sand mold and considering its cooling rate has been proposed (Patent Document 1: Japanese Patent Laid-Open No. 2002-307158). In Patent Document 1, for the purpose of reducing the amount of circulating casting sand used and adjusting the cooling time for each casting, the casting temperature is lower than the solidus temperature after casting the molten metal into the green sand mold. Primary cooling is performed until then, and the parts of the green sand mold that are not affected by heat are destroyed and separated and removed, and the castings that are wrapped in the remaining sand that is affected by heat are attributed to each casting. The casting cooling method which performs secondary cooling for the corresponding time is described. In addition, this patent document 1 does not describe the material of the casting.

JP 2002-307158 A

  However, a method of casting an aluminum or aluminum alloy casting with a mold using green sand has not been conventionally performed, and Patent Document 1 does not disclose such a method. This is because when casting a molten aluminum or aluminum alloy, if the cooling rate in the vicinity of the solidus is not sufficiently high, a fine cast structure cannot be obtained, and the quality of the cast product after casting will be low. It is. That is, conventional aluminum or aluminum alloy castings employ a method using a mold such as a mold casting method in order to ensure a necessary cooling rate.

  The present invention has been made in view of such problems, and makes it possible to cast a molten aluminum or aluminum alloy with a sand mold using fresh sand, thereby significantly improving productivity. Or it aims at providing the casting method of an aluminum alloy casting.

  The casting method of the aluminum or aluminum alloy casting according to the present invention includes a step of creating a sand mold, a step of injecting a molten aluminum or aluminum alloy into the sand mold, and a step of cooling the casting together with the sand mold with water or a liquid refrigerant. And a step of dismantling the sand mold.

  In the casting method of the aluminum or aluminum alloy casting, the step of cooling with the water or liquid refrigerant is, for example, immersing the sand mold in water together with the casting.

  A method for producing an aluminum or aluminum alloy casting according to the present invention comprises a step of creating a unit sand mold having cavities on the front and rear surfaces in the line direction in a molding chamber of a casting line, and a plurality of unit sand molds on the line are arranged on the front surface and A process of injecting molten aluminum or aluminum alloy into the cavity from a pouring port provided on the overlapping surface by overlapping on the rear surface, and a unit of the connected sand mold after injection for each unit sand mold or units It has the process of cut | disconnecting in the middle of a sand mold, and immersing in water or a liquid refrigerant | coolant, and the process of disassembling the said sand mold.

  In this casting method of aluminum or aluminum alloy casting, it is preferable to have a step of drying the sand after the sand mold dismantling and then supplying it to the molding chamber for reuse.

  In the present invention, after casting a molten aluminum or aluminum alloy into a sand mold, it is cooled by a method such as immersion in water or liquid refrigerant together with the sand mold, and the casting is rapidly cooled. As in the case of this, the structure of the casting becomes fine, and a high-strength aluminum or aluminum alloy casting can be obtained. Moreover, in this casting method using sand molds, it is the sand mold molding process that limits the line speed, but the sand mold molding work is relatively short, and it is also possible to mold with multiple lines. As such, the sand molds can be sequentially fed at a sufficient rate. On the other hand, in the case of the mold casting method, the molten metal injection process, the cooling process, and the mold opening process are sequentially performed by one casting machine, and if the casting of one casting is not completed, the next casting process is started. It is not possible. For this reason, in the case of the die casting method, the productivity is extremely low, but the productivity is remarkably improved by using the sand mold as in the present invention.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 is a process diagram showing a process of a casting method for aluminum or aluminum alloy castings according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view showing a molding process, and FIG. 3 is a schematic perspective view showing a molten metal injection process. 4 is a schematic diagram showing a cooling process, and FIG. 5 is a schematic perspective view showing a sand mold spreading process. As shown in FIGS. 2 and 3, the molding and the molten metal pouring process are performed on the same line. That is, first, a mold (hereinafter referred to as a sand mold) is manufactured using green sand in the molding chamber 1. In the molding chamber 1, a mold 2 provided with a cast-shaped portion 3 having a half-shaped shape of a cast product on one side surface thereof can be rotated by a horizontal rotating shaft 4 provided above the chamber 1. It is supported by. Similarly, on the other side surface of the molding chamber 1, a mold 6 provided with a cast-shaped portion 5 having a half-shaped shape of a cast product is fixed to a piston 7 of a hydraulic cylinder. Thereby, the metal mold | die 6 presses the sand between them with the metal mold | die 2 by advance of the piston 7, and molds it. Note that sand is supplied to the molding chamber 1 from its upper surface, and this sand is sand after sand processing described later, and sand for sand mold is circulated and used.

  After molding, the mold 2 is rotated upward about the rotating shaft 4, and the sand mold 10 after molding (hereinafter also referred to as a unit sand mold) is pushed by the piston 7 by the drive of the hydraulic cylinder, and the front conveyor ( PMC: Precision mode conveyor (product name)) 11 is extruded. The conveyor 11 extends in a direction in which the mold 2 and the mold 6 face each other, and the sand mold 10 formed in the molding chamber 1 is pushed by the piston 7 and transferred onto the conveyor 11. By driving, it moves in a direction away from the molding chamber 1.

  Thereafter, the core 12 is inserted into the recesses formed on the front and rear side surfaces of the unit sand mold 10, and the front unit sand mold 10 and the rear unit sand mold 10 on the conveyor 11 are respectively connected to the rear side surface and The connected sand molds 18 are overlapped on the front side surface, and a cavity 14 as a casting space is formed in the overlapped portion. It should be noted that an injection port 13 for injecting molten metal is formed in the lower portion of the cavity 14 during this superposition.

  After that, as shown in FIG. 3, molten aluminum 22 of aluminum or aluminum alloy melted in the melting furnace 20 is supplied to the pressure type pouring machine 21, and the molten metal 22 is supplied from the pressure type pouring machine 21 through the gate 22. Then, the pressure is supplied to the pouring port 13 between the unit sand molds 10 and injected into the cavity 14 through the pouring port 13.

  Thereafter, the connected sand mold 18 is cut by a sand mold cutter 17 for a plurality (three in the illustrated example) of unit sand molds 10. That is, in the case of the illustrated example, a substantially middle part of one unit sand mold 10 is cut perpendicularly to the connecting direction, two unit sand molds 10 are placed, and a substantially middle part of the third unit sand mold 10 is similarly cut. To do. As a result, as shown in FIG. 4, the connected sand molds 18 that have been fed out from the molding chamber 1 and then connected are divided into connected sand molds 18 having a length corresponding to three unit sand molds. Then, it transfers from the molding injection line (conveyor 11) on the mesh conveyor 23 of a cooling line.

  Next, as shown in FIG. 4, the connected sand mold 18 is lowered into the cooling water 31 in the water tank 30 using a lifter, and is cooled by being immersed in water. The temperature of the molten metal in the sand mold at the start of the water cooling is preferably just above the solidus line of aluminum or aluminum alloy, and is rapidly cooled by water cooling and dropped to around room temperature. Thereafter, the connected sand mold 18 is taken out of the water by a lifter and sent to the next sand mold spreading process.

  In the sand mold separation process, the sand mold is disassembled on the vibration feeder 40 that is supplied to the vibration feeder 40 for each unit sand mold 10 and vibrates by the eccentric cam 41. Collected on the feeder 40.

  The sand separated by the vibration feeder 40 falls onto the sand receiver 42, and is heated and dried by the burner 43 on the sand receiver 42. Thereafter, the sand is cooled in the cooling tank and then transferred onto the belt conveyor 45. The sand is supplied to the molding chamber 1 shown in FIG. In this way, the sand used for molding is recycled.

  The surface of the obtained casting 33 is polished by shot blasting to be finished into a product such as an aluminum wheel for automobiles.

  As described above, in the present embodiment, the molten aluminum or aluminum alloy is cast into a sand mold (unit sand mold 10) using green sand, and is immersed in water together with the sand mold from a temperature immediately above the solidus temperature to be rapidly cooled. Therefore, a fine cast structure can be obtained as in the case of casting by the mold casting method, and a high-quality casting can be obtained. Moreover, in this embodiment, the line speed is controlled by sand mold molding, but the time required for molding one sand mold 10 is short, and the sand mold can be molded by a plurality of lines. The number of castings that can be manufactured per round is high and the productivity is high. Therefore, like the mold casting method which is a conventional casting method of aluminum or aluminum alloy melt, after injecting the molten metal, wait for cooling, then open the mold and take out the casting, then assemble the mold, Compared to the case where the next casting process must be started after a series of molding, pouring and cooling processes are completed, such as injecting the molten metal in the next order, the method of the present invention significantly improves productivity. Can do.

  In addition, this invention is not restricted to the said embodiment, A various deformation | transformation is possible. For example, as a water cooling method, there is a method such as jetting of cooling water in addition to immersion in water. There is also a method of immersing in a liquid refrigerant instead of water cooling. In any case, the cooling rate of the casting can be remarkably increased as compared with the case of the conventional sand mold casting. Further, since the unit sand mold shown in FIG. 2 is provided with cavities that are half of the casting to be cast on the front and rear surfaces of each unit sand mold, one casting is cast. However, the present invention is not limited thereto, and a plurality of half cavities are formed in one unit sand mold by forming a plurality of half cavities on the front and back sides in the direction in which the unit molds are connected. Can be cast.

It is process drawing which shows the process of the casting method of the aluminum or aluminum alloy casting which concerns on embodiment of this invention. It is a longitudinal cross-sectional view which shows a molding process. It is a typical perspective view which shows a molten metal injection | pouring process. It is a schematic diagram which shows a cooling process. It is a typical perspective view which shows a sand mold spreading process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Molding chamber 2, 6; Die 3, 5; Cast-shaped part 7; Hydraulic cylinder 10; Unit sand mold 11: Conveyor (PMC)
12; Core 13; Pouring port 14; Cavity 17; Cutter 18; Connected sand mold 20; Melting furnace 21; Pressurized pouring machine 22; Molten metal 23: Conveyor (mesh conveyor)
30; Water tank 31; Cooling water 33; Casting 40; Vibrating feeder 45; Belt conveyor

Claims (4)

  A step of creating a sand mold, a step of injecting a molten aluminum or aluminum alloy into the sand mold, a step of cooling a casting together with the sand mold with water or a liquid refrigerant, and a step of disassembling the sand mold. A casting method of aluminum or aluminum alloy casting.   2. The method for casting an aluminum or aluminum alloy casting according to claim 1, wherein the water cooling step comprises immersing the sand mold in water or a liquid refrigerant together with the casting.   A step of creating a unit sand mold having cavities on the front and rear surfaces in the line direction in a molding chamber of a casting line, and a plurality of unit sand molds on the line are overlapped on the front and rear surfaces to form a connected sand mold. A step of injecting molten aluminum or aluminum alloy into the cavity from the pouring gate, and cutting the connected sand mold after injection into one or a plurality of unit sand molds in the middle of the unit sand mold and immersing them in water or liquid refrigerant A casting method of aluminum or an aluminum alloy casting, characterized by comprising: a step of: and a step of dismantling the sand mold.   A method for casting an aluminum or aluminum alloy casting, comprising: drying the sand after dismantling the sand mold and supplying the sand to the molding chamber for reuse.

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