JP2002273561A - Method and apparatus for producing cast body having unidirectional solidified structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for producing a cast body having uniform unidirectional solidified structure to the whole body. SOLUTION: A mold 33 provided with a through-hole 8 at the bottom part is prepared and further, a slide plate 7 having a slide hole 6 having the diameter of the same as or not larger than that of the through-hole 8 is prepared, and the through-hole 8 is plugged by inserting the slide plate 7 into a slide passage 9 arranged at the bottom part of the mold 33, and the mold 33 having such a structure is laid on a chill plate 1 for cooling the mold 33 by letting coolant flow. Successively, raw material is charged into the mold 33 and heated and melted by energizing an upper heater 4, and after fully melting the raw material, the molten metal 12 is brought into contact with the chill plate 1 by shifting the slide plate 7 so that the slide hole 6 concentrically piles up with the through- hole 8 and the molten metal 12 is cooled from the bottom part with the cooling of the chill plate 1. On the other hand, the energizing quantity to the upper heater 4 is reduced step by step or continuously.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a cast having a directionally solidified structure.

[0002]

2. Description of the Related Art A chill plate 1 as shown in a sectional view of FIG.
A mold 3 placed on the mold 3, an upper heater 4 provided above the mold 3, and a heat insulating material 5 surrounding the periphery of the mold 3 are provided. Casting production equipment is already known. In order to manufacture a cast body having a unidirectional solidification structure using this apparatus, first, a solid raw material (not shown) is charged into a mold 3 on a chill plate which is cooled by flowing a coolant. The power is supplied to the upper heater 4 to heat and melt the raw material. After the raw material is completely dissolved, the amount of power supplied to the upper heater 4 is reduced stepwise or continuously so that the temperature of the upper heater 4 is gradually or continuously increased. By controlling the heating of the upper heater 4, the molten metal 12 in the mold is solidified from the lower part to the upper part, thereby producing a cast body having a unidirectional solidification structure. It is said that a method and an apparatus for producing a cast having a unidirectionally solidified structure using the above-described apparatus are particularly effective for producing a silicon substrate having a large area unidirectionally solidified structure at low cost. In addition, this apparatus requires only one heating mechanism and does not require a movable mechanism, so that the equipment is greatly simplified, and since this method has no step of pouring molten metal, there is no oxide wrapping. There are advantages such as.

[0003]

However, according to this method and apparatus, even if the raw material in the mold 3 is to be heated and melted by the upper heater 4, the bottom of the mold 3 is provided in contact with the chill plate 1 and is cooled. Therefore, it takes a long time until the upper heater 4 is energized to completely dissolve the raw material. On the other hand, if the thickness of the bottom of the mold 3 is increased to reduce the influence of the chill plate 1 and thereby shorten the melting time, the cooling of the molten metal at the bottom of the mold does not proceed during the cooling and solidification process after melting. Since the temperature gradient required for directional solidification cannot be easily obtained, there is a problem that a coarse uniaxial solidification structure of poor quality is formed due to generation of coarse equiaxed crystals and solidification defects.

[0004]

Means for Solving the Problems Accordingly, the present inventors have:
Research was conducted to solve this problem. As a result, as shown in the sectional view of FIG. 1, a mold 33 having a through hole 8 at the bottom is prepared, and a slide plate 7 having a slide hole 6 having a diameter equal to or smaller than the through hole 8 is prepared.
And the slide plate 7 is inserted into a slide passage 9 provided at the bottom of the mold 33 to close the through-hole 8, and the chill plate 1 is cooled by flowing a coolant through the mold 33 having such a structure.
The mold 33 is fixed by the mold frame 2, and then the raw material is charged into the mold 33, and the upper heater 4 is energized to heat and melt the raw material. Slide plate 7 so that 6 overlaps concentrically with through hole 8
Is moved to contact the molten metal 12 with the chill plate 1 and cooled by the chill plate 1 so that the molten metal 12 is cooled from the bottom of the mold. The effect of cooling the plate 1 can be avoided. On the other hand, when the molten metal is cooled, the molten metal can be cooled efficiently by directly contacting the chill plate 1, and the cooling of the molten metal 12 by the chill plate 1 is accelerated to one-way solidification. The research results showed that the temperature gradient required for the process was obtained, and that a cast having a uniform unidirectional solidification structure throughout could be easily produced.

The present invention has been made based on the above research results. (1) After heating and melting a raw material in a mold, the molten metal in the mold is solidified sequentially from below to above. In the method for producing a casting having a directionally solidified structure, a method for producing a casting having a directionally solidified structure in which molten metal in a mold immediately after melting is brought into direct contact with a chill plate, and more specifically, (2) an inner bottom portion of the mold 33 A mold 33 having a through hole 8 penetrating from the bottom to the outer bottom and a slide passage 9 provided at the bottom from one wall surface to the other wall surface of the mold is prepared. A slide plate having a slide hole 6 and a flat portion 11 is inserted into the mold, the through-hole 8 of the mold is closed by the flat portion 11 of the slide plate 7, and the raw material is charged into the mold while maintaining this state. The upper heater 4 is energized to heat and melt the raw material. After the raw material is completely melted, the slide plate 7 is moved so that the slide hole 6 of the slide plate 7 overlaps the through hole 8 of the mold to chill the molten metal 12. Unidirectional solidification structure in which the heating capacity of the upper heater is reduced stepwise or continuously by bringing the molten metal into direct contact with the plate and cooling the molten metal from the bottom of the mold, and at the same time, gradually or continuously reducing the amount of electricity supplied to the upper heater 4. And a method for producing a cast body having the following characteristics.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An apparatus for carrying out the method for producing a cast having a unidirectionally solidified structure of the present invention described in the above (1) and (2) will be described in further detail. FIG. 2 is a perspective view of a mold 33, which is the most characteristic part of the apparatus for carrying out the method for producing a cast having a directionally solidified structure according to the present invention. The mold 33 is made of graphite. The bottom of the mold 33 is provided with a through hole 8 penetrating from the inner bottom to the outer bottom, and a slide passage 9 is provided at the bottom from one wall surface of the mold 33 to the other wall surface. Have been. A slide plate 7 having a slide hole 6 and a flat portion 11 is provided in a slide passage 9 of the mold 33.
3, the through hole 8 at the bottom of the mold 33 is closed by the flat portion 11 as shown in the plan view of FIG. The slide plate 7 is made of graphite, and the diameter of the slide hole 6 provided in the slide plate 7 is
It is preferable that the diameter is equal to or smaller than the diameter. If the diameter of the slide hole 6 is larger than the diameter of the through hole 8, the molten metal will enter the slide hole 6, and if it hardens, it will not easily come off. The mold 33 is placed on the chill plate 1 and fixed by the mold frame 2, whereby the slide plate 7 is fixed so as not to move even when the slide passage 9 provided at the bottom of the mold 33 is slid. .

[0007] As shown in FIG.
The raw material is charged into the mold 33 while the through hole 8 of the mold is closed by the flat portion 11 of the upper heater 4.
And the raw material is heated and melted. At this time, it is possible that the refrigerant does not flow through the chill plate 1. After the raw material is completely dissolved, as shown in the plan view of FIG. 4, the slide plate 7 is moved so that the slide hole 6 is concentrically overlapped with the through hole 8 of the mold, and the molten metal is moved. 12
Is brought into direct contact with the chill plate 1, the chill plate 1
The molten metal that has contacted with the molten metal is rapidly cooled, and the surface of the molten metal is heated by the upper heater 4, so that a temperature gradient sufficient to form a unidirectional solidified structure above and below the molten metal is formed.

A mold 33 placed on the chill plate 1
Is surrounded by a heat insulating material 5 as shown in FIG. The heat insulating material 5 mainly uses a heat insulating material of fibrous carbon. The upper heater 4 uses a carbon heater. Further, the chill plate 1 of the present invention may be made of copper having excellent heat conductivity, but may be made of a heat-resistant alloy, for example, stainless steel. It is preferable that a release agent is applied to the chill plate 1 in advance to prevent seizure of the molten metal and the chill plate.

Example 1 A cavity having dimensions of an inner diameter of 120 mm and a depth of 100 mm, a thickness of a bottom portion of 30 mm, a diameter of a through hole provided in the bottom portion of 60 mm, and a thickness of A graphite mold provided with a slide passage was prepared. A slide plate having a slide hole having a diameter of 55 mm is inserted into the slide passage of the graphite mold so that the through hole is closed,
2 kg of an Al raw material was inserted into the cavity of the mold, and electricity was supplied to an upper heater provided above to dissolve the Al.
After completely dissolving, the slide plate is moved so that the through hole and the slide hole overlap concentrically, and the resulting Al melt is brought into contact with the chill plate through which the cooling water is flowing, and the amount of electricity supplied to the upper heater is reduced. Upon continuous reduction, an ingot having a uniform unidirectionally solidified structure throughout was obtained.

Conventional Example 1 For comparison, a cavity having the dimensions of an inner diameter of 120 mm and a depth of 100 mm was provided, and the thickness of the bottom was 15 mm.
Prepare a normal graphite mold with 2 kg of Al raw material in the cavity of this graphite mold, and supply electricity to the upper heater provided above to dissolve Al and reduce the amount of electricity to the upper heater continuously. As a result, coarse equiaxed crystals were generated, an ingot having a uniform unidirectionally solidified structure throughout was not obtained, and solidification defects were also generated.

[0011]

By using the mold of the present invention, it is possible to more easily produce a cast having a uniform unidirectional solidified structure as a whole.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional explanatory view showing an apparatus for producing a cast having a directionally solidified structure of the present invention.

FIG. 2 is a perspective view of a mold used in the apparatus for manufacturing a cast having a directionally solidified structure of the present invention.

FIG. 3 is a plan view of a mold used in the apparatus for manufacturing a cast having a directionally solidified structure of the present invention.

FIG. 4 is a plan view of a mold used in the apparatus for manufacturing a cast having a directionally solidified structure of the present invention.

FIG. 5 is a schematic sectional view showing a conventional apparatus for producing a cast having a unidirectionally solidified structure.

[Description of Signs] 1 Chill plate 2 Mold frame 3 Mold 4 Upper heater 5 Insulation material 6 Slide hole 7 Slide plate 8 Through hole 9 Slide passage 10 Container 11 Flat part 12 Melt 33 Mold

Claims (4)

[Claims] 1. A method for producing a cast body having a unidirectional solidification structure in which a raw material in a mold is heated and melted in a mold and then solidified from bottom to top in a sequential manner. A method for producing a cast body having a unidirectionally solidified structure, which is brought into direct contact with a chill plate. 2. A mold having a through hole penetrating from the inner bottom to the outer bottom of the mold and a slide passage provided at the bottom from one wall surface to the other wall surface of the mold is prepared. A slide plate having a slide hole and a flat portion is inserted into the slide passage of the mold, and the raw material is charged into the mold while maintaining a state in which the through hole of the mold is closed by the flat portion of the slide plate. When the raw material is heated and melted by applying power, the raw material is completely melted, and then the slide plate is moved so that the slide hole of the slide plate overlaps the through hole of the mold, and the molten metal is brought into direct contact with the chill plate. A one-way method characterized in that the heating temperature of the upper heater is reduced stepwise or continuously by gradually or continuously decreasing the amount of electricity supplied to the upper heater while cooling from the bottom. Method for producing a casting having a solid tissue. 3. A mold having a through hole penetrating from the inner bottom to the outer bottom of the mold and a slide passage provided at the bottom from one wall surface to the other wall surface of the mold; A slide plate having a slide hole having a diameter equal to or smaller than the through hole and having a diameter penetrating in the thickness direction, wherein the slide plate is removably inserted into the slide passage. A casting mold manufacturing mold having a characteristic unidirectional solidification structure. 4. A mold having a through-hole penetrating from the inner bottom to the outer bottom of the mold and a slide passage provided at the bottom from one wall surface to the other wall surface of the mold; A slide plate having a slide hole having a diameter equal to or smaller than the through hole and having a diameter penetrating in a thickness direction, a chill plate through which a coolant can flow and cooled, A mold frame for fixing on the plate, an upper heater provided at a distance above the mold, and a heat insulating material surrounding at least the periphery of the mold, and the slide plate is provided at the bottom of the mold. A cast body having a unidirectional solidification structure, wherein the cast body has a structure mounted on the chill plate and fixed by a mold frame in a state in which the slide body is removably inserted into a provided slide passage. Manufacturing equipment.