JPH05220567A - Method and device for cooling unidirectional solidifying furnace - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a method and an apparatus for cooling a unidirectional solidification furnace. [Structure] After the metal material 3 is accommodated in a molten state in the container 2 and the container 2 is placed in a microgravity state, one second pressure chamber 23d, 21d is opened to the atmosphere and the other second pressure chamber 21d, 23d is supplied with pressurized air, and the cooling medium A contained in the other first pressure chambers 21c and 23c is jetted from the other jet nozzles 25 and 27 to cool the bottom portion 2b of the container 2 in a microgravity state. The unidirectional solidification is applied to at least the bottom of the metal material 3 while sucking the cooling medium A from one of the injection nozzles 27 and 25 and collecting the cooling medium A into the one of the first pressure chambers 23c and 21c. [Effect] Good unidirectionally solidified metal can be obtained in a microgravity environment for a short time by using a cooling device of a relatively small unidirectionally solidified furnace.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cooling a directional solidification furnace for microgravity and an apparatus therefor.

[0002]

2. Description of the Related Art Conventionally, a microgravity experiment (substantial weightlessness experiment) utilizing free fall of a falling body on the ground has been performed. The falling body used in this type of experiment is disclosed in, for example, Japanese Patent Laid-Open No. 1-266100. During the free fall of the falling body, a microgravity experiment is performed on the ground by using the space equipment, physical and chemical experimental equipment installed inside the falling body. In such a microgravity experiment, a unidirectionally solidified metal that does not cause a crystal interface crack is satisfactorily obtained by giving a temperature gradient to a molten metal material and growing a crystal in one direction. And under microgravity, there is no heat convection due to the non-uniformity of temperature,
It can be expected that a unidirectionally solidified metal in which the growth is not disturbed and crystals are aligned and has no defects is unidirectionally grown at a higher solidification rate.

However, conventionally, in the free-fall type microgravity experiment, there was no furnace capable of unidirectionally solidifying well because of time and size restrictions of experimental equipment. In other words, in a free-fall microgravity experiment on the ground, the microgravity time can be obtained for only about 10 seconds at the maximum, and the size of the dropping capsule for mounting the experimental equipment is limited. This is because the cooling rate and the temperature gradient of the furnace are important control parameters for unidirectional solidification.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional technical problems, and a cooling method for a unidirectional solidification furnace has a structure in which both ends of one piston rod are provided. It has a pair of cylinder devices in which each cylinder is divided into a first pressure chamber and a second pressure chamber by a provided piston, a base end portion is connected to each first pressure chamber, and a tip end is provided at a bottom portion of the container. Each have a nozzle for injection facing each other, and a pressure air supply source or the atmosphere can be selectively connected to each second pressure chamber via a switching valve, and a metal material is accommodated in a molten state in the container, After being placed in the microgravity state, pressure air is supplied to the other second pressure chamber in a state where one of the second pressure chambers is opened to the atmosphere, and the cooling medium contained in the other first pressure chamber is injected into the other injection nozzle. From the bottom of the container under microgravity. Together to retirement, while collecting the cooling medium into the first pressure chamber of one and sucked cooling medium from one of the injection nozzle, characterized in providing a directionally solidified at least on the bottom of the metal material. Further, the configuration of the cooling device of the one-way solidification furnace is a cooling device of the one-way solidification furnace to be used in microgravity experiments, and a container for containing a metal material,
A heater capable of maintaining the molten state of the metal material in the container,
A cooling medium reservoir that covers the bottom of the container, and a pair of cylinder devices that divide the inside of each cylinder into a first pressure chamber and a second pressure chamber by pistons provided at both ends of one piston rod, A base end portion is connected to each of the first pressure chambers for containing the cooling medium, an injection nozzle whose tip faces the bottom portion of the container covered with the cooling medium reservoir, and a switching valve for each of the second pressure chambers. And a cylinder drive device capable of selectively connecting a pressure air supply source or the atmosphere. Then, a control heater for maintaining the upper end of the metal material at a predetermined temperature equal to or higher than the melting temperature can be arranged on the upper portion of the container.

[0005]

A metal material such as an aluminum alloy or a copper alloy is put in a container as it is or in a molten state, and this container is fixed on a cooling medium reservoir in a dropping capsule, for example. The temperature of the heater is raised to heat the inside of the container to maintain the molten state of the metal material. Next, the falling capsule is allowed to fall freely to give the container a microgravity state. After this microgravity condition, the heater is de-energized and the cylinder driving device is driven. That is, the switching valve is appropriately switched to open one of the second pressure chambers to the atmosphere and supply the pressure air from the pressure air supply source to the other second pressure chamber on the side where the piston is returning.

Thus, the cooling medium in the other first pressure chamber is ejected from the tip of the other injection nozzle. The cooling medium ejected from the tip of the other injection nozzle is used for cooling the bottom of the container, and is directly or temporarily stored in the cooling medium reservoir and then sucked from the tip of the one injection nozzle, It returns to one of the first pressure chambers. As a result, the bottom of the container is rapidly cooled by the cooling medium, and the metal material is rapidly cooled and solidified in a short time. When the cooling medium in the other first pressure chamber alone is insufficient for cooling, the switching valve is appropriately switched to open the other second pressure chamber to the atmosphere, and the pressure air is supplied to the one second pressure chamber. The pressurized air from the supply source is supplied, and the cooling medium returning to one of the first pressure chambers is ejected from the tip of one of the ejection nozzles.

Since the unidirectionally solidified state of the metal material thus obtained is in a microgravity environment, the heat convection movement due to the non-uniformity of temperature hardly occurs, and the bottom of the container is cooled. Since the medium is forcibly cooled and the heat is extracted in almost one direction, formation of equiaxed crystals is suppressed, and a solidified structure in which columnar crystals are well formed can be obtained. Thus, good unidirectional solidification is provided to at least the bottom of the metal material contained in the container. Then, the properties such as the service temperature of the unidirectionally solidified metal material taken out from the container can be known. If a control heater for holding the upper end of the metal material at a predetermined temperature is arranged in the upper part of the container, in the unidirectional solidification process of the metal material under a microgravity environment, the solidification rate and solidification surface of the metal material The temperature gradient can be maintained arbitrarily.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows one embodiment of a cooling device for a unidirectionally solidifying furnace according to the present invention. In FIGS. 1 and 2, reference numeral 1 indicates a cooling device for a unidirectional solidification furnace, which is housed inside the falling capsule 10 shown in FIGS. Weightless experiment).

Next, the cooling device 1 for the unidirectional solidification furnace will be described with reference to FIG. 2 is a container having a cylindrical shape with a bottom, in which the metal material 3 is housed, the pressing plate 4 is placed,
A lid 6 is screwed on via a coil spring 5. The container 2, the holding plate 4, the coil spring 5, and the lid 6 all have a melting temperature equal to or higher than the melting temperature of the metal material 3. A control heater 7 is arranged above the outer periphery of the cylindrical container body 2a of the container 2. The control heater 7 has a function of heating the upper portion of the container body 2a to hold the metal material 3 at a predetermined temperature, and is connected to a control temperature controller 9 capable of setting the control heater 7 at a predetermined temperature. There is. Further, a heater 11 is arranged on the outer peripheral side of the container 2 and the control heater 7, and the heater 11
Is connected to a temperature controller 13 capable of setting a predetermined temperature. The heater 11 can generate an amount of heat capable of melting the solid metal material 3 in the container 2.

The bottom portion 2b of the container 2 has a container body 2a.
If necessary, a spacer 15 that protrudes like a flange and has substantially the same size and poor thermal conductivity is closely attached to the bottom surface. The bottom portion 2b of the container 2 in which the spacer 15 is interposed is placed on a box-shaped cooling medium reservoir 17 so as to close the upper opening 17a, and is detachably fixed by a fixing tool (not shown). The bottom portion 2b is covered with a cooling medium reservoir 17. In this cooling medium reservoir 17, a pair of cylinder devices 21, 2 is installed.
3, the tip portions of the injection nozzles 25, 27 whose base end portions are connected to the respective first pressure chambers 21c, 23c, which will be described later, protrude, and the tip portions of the injection nozzles 25, 27 are connected to the container 2 via the spacer 15. It faces the bottom 2b.

In the pair of cylinder devices 21 and 23, the cylinders 21a and 23a are arranged symmetrically, and the pistons 21b and 23b are respectively provided at both ends of one piston rod 24 which penetrates the through hole 22a of the boundary wall portion 22. The first pressure chamber 21 is fixed on both sides of each piston 21b, 23b.
c, 23c and the second pressure chambers 21d, 23d are partitioned. A liquid cooling medium A (water, low melting point alloy, etc.) is housed in both the first pressure chambers 21c and 23c.

On the other hand, the second pressure chambers 21d and 23d are provided with pipes 40 and 4 equipped with pressure regulating valves 40a and 41a, respectively.
1 is connected to the pressurized air supply source 28 via a three-way switching valve 42, and the switching valves 30a, 30a and 3 are switching valves, respectively.
It is connected to the atmosphere by the pipes 32 and 33 provided with 1a. The pressure air supply source 28, the pipes 40 and 41, the three-way switching valve 42, the pressure adjusting valves 40a and 41a, and the pipes 32 and 3
3 and the on-off valves 30a and 31a, each second pressure chamber 21
3-way switching valve 42 or on-off valve 3 which is a switching valve at d and 23d
The cylinder drive device 35 is configured to selectively connect a pressure air supply source or the atmosphere via 0a and 31a.

Next, the operation of the above embodiment will be described. Metal material 3 such as aluminum alloy or copper alloy in the container 2
As a solid, and if necessary, a cooling medium reservoir 17 in the falling capsule 10 with a spacer 15 of a predetermined thickness interposed.
Fix on top. The temperature of the heater 11 is raised by operating the temperature controller 13 whose set temperature is equal to or higher than the melting temperature of the metal material 3,
The inside of the container 2 is heated. As a result, the metal material 3 is melted. The melted metal material 3 is elastically pressed by the pressing plate 4 whose upper surface receives the elastic force of the coil spring 5, so that the container 2 is filled with the space such as bubbles disappearing.

Next, the falling capsule 10 is lifted from the sand 37 in the sand box 36 installed on the ground surface GL to an appropriate height h (actually several tens of meters) as shown in FIG. Separate 10 and let it fall freely. Immediately before the drop capsule 10 is cut off, the control temperature controller 9 whose preset temperature is set to a predetermined temperature is operated to raise the temperature of the control heater 7, and the upper end portion of the metal material 3 is held at the predetermined temperature. The solidification rate and the temperature gradient of the solidification surface of the metal material 3 during the fall of 10 are arbitrarily maintained.

Immediately after separating the falling capsule 10,
That is, the metal material 3 in the container 2 is melted and placed in a microgravity state, and then the heater 11 is operated by operating the temperature controller 13.
The cylinder drive device 35 is driven while the power supply to the cylinder is cut off. That is, the opening / closing valves 30a and 31a are appropriately switched to open one of the second pressure chambers 23d or 21d to the atmosphere, and the three-way switching valve 42 is appropriately switched to set the boundary wall 2
To the other second pressure chamber 21d or 23d on the side where the pistons 21b and 23b return to the second side.
Supply pressurized air from 8.

Specifically, one on-off valve 31a or 30
The other pipe 4 whose pressure is set by the pressure adjusting valve 40a or 41a by switching the three-way switching valve 42 in a state in which a is opened and one of the second pressure chambers 23d or 21d is opened to the atmosphere.
The pressure air from the pressure air supply source 28 is supplied to the other second pressure chamber 21d or 23d through 0 or 41. Then, the cooling medium A in the other first pressure chamber 21c or 23c is ejected from the tip of the other injection nozzle 25 or 27 with the ejection pressure adjusted. The cooling medium A jetted from the tip of the other jet nozzle 25 or 27 is used for cooling the bottom portion 2b of the container 2 via the spacer 15, and then directly or once stored in the cooling medium reservoir 17. It is sucked from the tip of one of the injection nozzles 27 or 25 and returns to the one of the first pressure chambers 23c or 21c.

As a result, the first pressure chamber 21c or 23c
The cooling medium A stored in the jet nozzle 25 is jetted from the jet nozzle 25 or 27 to rapidly cool the bottom 2b of the container 2 in a microgravity state, and the metal material 3 is rapidly cooled and solidified in a short time (within 10 seconds). Together with one of the injection nozzles 27 or 25
The cooling medium A is sucked from the cooling medium A and is collected in the first pressure chamber 23c or 21c. Bottom 2b of container 2
Has a large area projecting like a flange from the container body 2a, so that the inside of the container 2 can be quickly cooled, and the thickness of the spacer 15, the thermal conductivity, etc. can be changed to cool this container. The speed and temperature gradient can be adjusted arbitrarily.

The other first pressure chamber 21c or 23c
When the cooling medium A in the inside is insufficient for cooling, the three-way switching valve 42 and the opening / closing valves 30a and 31a are appropriately switched to open the other second pressure chamber 21d or 23d to the atmosphere, and the one second The pressure air from the pressure air supply source 28 is supplied to the pressure chamber 23d or 21d, and one of the first pressure chamber 23c or 2 is supplied.
1 c of the cooling medium A returning to 1c
Eject from the tip of 7 or 25. Since the unidirectionally solidified state obtained in this way is under a microgravity environment, there is almost no thermal convection movement due to a nonuniform temperature difference, and the bottom 2b of the container 2 is cooled by the cooling medium A. Since it is forcibly cooled and heat is extracted in one direction,
The formation of equiaxed crystals is suppressed, and a solidified structure in which columnar crystals are well formed is obtained.

Thus, good unidirectional solidification is given to at least the bottom of the metal material 3 contained in the container 2. Then, the unidirectionally solidified metal material 3 taken out from the container 2
It is possible to know the properties such as the service temperature of. By the way, the above-mentioned microgravity state is almost similarly given to the free descent of the aircraft, and it is needless to say that the same action can be obtained even in the completely weightless state. Further, when the molten metal material 3 is put in the container 2, the heater 11 may have the ability to maintain the molten state of the metal material 3.

[0020]

As can be understood from the above description,
According to the cooling method for a unidirectional solidification furnace and the apparatus therefor of the present invention, a good unidirectionally solidified metal is obtained under a microgravity environment for a short time by using a cooling device for a relatively small unidirectional solidification furnace. The effect of being able to be played.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a cooling device for a unidirectional solidification furnace according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a drop capsule of the same.

FIG. 3 is an explanatory view showing a drop test of a drop capsule in the same manner.

[Explanation of symbols]

1: Cooling device for unidirectional solidification furnace, 2: Container, 2a: Container body, 2b: Bottom part, 3: Metal material, 4: Presser plate, 5: Coil spring, 6: Lid, 7: Control heater, 9 : Control temperature controller, 10: drop capsule, 11: heater, 13: temperature controller, 15: spacer, 17: cooling medium reservoir, 17a: upper opening, 21, 23: cylinder device, 21a, 23a: cylinder, 21b and 23b: pistons, 21c and 23c:
First pressure chamber, 21d, 23d: second pressure chamber, 25, 2
7: injection nozzle, 22: boundary wall, 22a: through hole, 2
4: Piston rod, 28: Pressure air supply source, 30a,
31a: open / close valve (switching valve), 32, 33: piping, 35:
Cylinder drive device, 40, 41: piping, 40a, 41
a: pressure adjusting valve, 42: three-way switching valve (switching valve), A: cooling medium.

Claims (3)

[Claims] 1. A pair of cylinder devices in which the interior of each cylinder is divided into a first pressure chamber and a second pressure chamber by pistons provided at both ends of one piston rod, and each first pressure is provided. The chamber has a base end connected to it, and a bottom end of the container has an injection nozzle whose front end faces each other, and a pressure air supply source or atmosphere can be selectively connected to each second pressure chamber via a switching valve. After the metal material is accommodated in a container in a molten state and the container is placed in a microgravity state, pressurized air is supplied to the other second pressure chamber with one second pressure chamber open to the atmosphere, and the other second pressure chamber is supplied. The cooling medium contained in one pressure chamber is jetted from the other jetting nozzle to cool the bottom of the container in a microgravity state, and the cooling medium is sucked from one jetting nozzle to the one first pressure chamber. While collecting the cooling medium into the metal material A method for cooling a unidirectional solidification furnace, characterized in that unidirectional solidification is applied to at least the bottom part of the. 2. A cooling device for a unidirectional solidification furnace used in a microgravity experiment, comprising a container for containing a metal material, a heater capable of maintaining a molten state of the metal material in the container, and a container for the container. A cooling medium reservoir that covers the bottom portion, a pair of cylinder devices that divide the inside of each cylinder into a first pressure chamber and a second pressure chamber by pistons provided at both ends of one piston rod, and a cooling medium are provided. A base end portion is connected to each of the first pressure chambers to be housed, and an injection nozzle whose tip faces the bottom portion of the container covered with the cooling medium reservoir, and pressurized air supply to each of the second pressure chambers through a switching valve. A cooling device for a unidirectional solidification furnace, comprising: a cylinder driving device capable of selectively connecting a source or an atmosphere. 3. The cooling device for a unidirectional solidification furnace according to claim 2, wherein a control heater for holding the upper end of the metal material at a predetermined temperature is arranged above the container.