JPH09133470A - Hot isotropic pressure application device and cooling method of the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten an in-furnace cooling time after HIP treatment without damaging an effective volume rate. SOLUTION: A reversed cup-shaped insulating layer 5 is provided inside a high pressure vessel 2, thereby surrounding a furnace compartment 6. This device is designed to treat an article 8 based on HIP treatment in the aforesaid furnace compartment 6 surrounded with the insulating layer. Gas distribution holes 15 and 16, which communicate the inside and the outside of the furnace compartment 6, are provided in the upper part and the lower part of an inner casing 11 in the insulation layer 5 where a second valve means is provided so as to open and close freely at least one of the distribution holes 15 and 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot isostatic pressing device (hereinafter referred to as a HIP device) used for removing defects in a cast product and a hot isostatic pressing process (hereinafter referred to as a HIP device) in the HIP device. , HIP treatment), specifically, a hot isotropic pressurization capable of shortening the cooling time and reliably preventing an excessive temperature rise of the high-pressure container. The present invention relates to a pressure device and a cooling method thereof.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for processing various materials under high temperature and high pressure, and as a device therefor, a HIP device has attracted attention. According to this HIP device, for example, powder materials such as metal powder or ceramic powder can be sintered under high pressure, and have higher density and higher strength as compared with those sintered under atmospheric pressure or vacuum. It has many advantages.
Further, the HIP device has a large number of microscopic pores inside (sometimes there are large pores observable with the naked eye), and by subjecting the ordinary product to high temperature and high pressure treatment, these pores are completely removed. Alternatively, it can be refined or reduced to such an extent that it does not hinder practical use, and as a result, strength can be improved, which plays a major role in removing casting defects and improving quality.

[0003] These HIP devices basically include an inverted cup-shaped heat insulating layer installed inside a high-pressure container capable of hermetically sealing high-pressure gas, and a heater provided in the furnace chamber inside the heat-insulating layer. Have. Further, a gas supply hole for pressurizing and injecting a pressure medium gas such as argon gas (hereinafter abbreviated as Ar gas) into the furnace chamber is provided in the high pressure vessel. The object to be processed is HIP-processed by the pressure medium gas of high temperature and high pressure in the furnace chamber. Of the above-mentioned components, the important one that controls the performance of the HIP device is the heat insulating layer, and since it is exposed to the special condition of high pressure, a structure different from the heat insulating layer of a normal high temperature furnace is required. . That is, in this type of device, the Ar gas used as the pressure medium is, for example, 196.
Under the conditions of 13 Mpa (2000 kg / cm ² ) and 1450 ° C., the viscosity is only 3.8 times that at room temperature and pressure, but the heat capacity per volume reaches 240 times or more. As described above, since Ar gas has a very large heat capacity, it is also rich in fluidity, and therefore the amount of heat transfer by convection is extremely large. Therefore, as the heat insulating layer, a layer that suppresses the outflow of the high temperature gas in the furnace chamber to the outside of the furnace chamber and suppresses the heat loss to a low level is used.

However, when such a heat insulating layer is used,
Since the cooling process after the HIP process will take time, many technologies have been proposed to achieve rapid cooling in the heat insulating layer. As an example, JP-A-59-87
There is a technique disclosed in Japanese Patent No. 032. This is shown in FIG. In the HIP device shown in FIG. 7, a heat insulating layer 51 is installed inside the high-pressure vessel 50 to form a furnace chamber 56 inside the heat insulating layer 51, and a heat storage body 58 is installed above the heat insulating layer 51. A flow path opening / closing adjusting mechanism 54 is installed below the
A processing table 53 for placing an object to be processed, an inner cylinder 52, and a heater 57 are arranged in the furnace chamber 56, and a forced stirring means 55 for stirring a pressure medium gas is installed below the processing table 53. There is.

In this technique (conventional example 1), during the HIP process, the flow path opening / closing adjusting mechanism 54 is closed as shown in FIG. 4 (a) so that the heated pressure medium gas does not come out of the furnace chamber 56. ing. Further, after the HIP process, the inside of the furnace chamber 56 is cooled, so that the flow path opening / closing adjusting mechanism 54 is opened as shown in FIG. The high-temperature pressure medium gas flows out of the heat insulating layer 51 from the upper portion of the heat insulating layer 51 through the heat storage body 58, and the heat insulating layer 51 and the high-pressure container 5
The space between 0 and 0 descends while being removed by the high-pressure container 50, passes through the flow path opening / closing adjusting mechanism 54, and the pressure medium gas forced stirring means 55.
And goes back into the furnace chamber 56. In this way, the furnace chamber 56
The inside is being cooled.

[0006] Next, as another conventional technique, Japanese Patent Publication No. 62-62
FIG. 8 shows the technique disclosed in Japanese Patent Laid-Open No. 58770. In the HIP device in FIG. 8, a heat insulating layer 61 is installed inside a high-pressure container 60 to form a furnace chamber 66 in the heat insulating layer 61, and an inner cylinder 62, a heater 67, and a first pressure medium are provided in the furnace chamber 66. A gas forced stirring means 65 is installed, and a second pressure medium gas forced stirring means 68 and a heat exchanger 69 are installed below the inside of the high pressure vessel 60.

In this technique (conventional example 2), after the HIP process, the first pressure medium gas forced stirring means 65 and the second pressure medium gas forced stirring means 68 are operated in order to cool the inside of the furnace chamber 66. The high-temperature pressure medium gas descends from the working space 63 from the upper side to the lower side, passes through the first pressure medium gas forced stirring means 65, and
The first circulation flow that rises in the space between the heat insulation layer 61 and the inner cylinder 62 from below the inner cylinder 62, and the space between the heat insulation layer 61 and the inner cylinder 62 rises, and the space between the heat insulation layer 61 and the high-pressure container 60 is increased. The second pressure is lowered while being removed by the high-pressure container 60, passes through the second pressure-medium gas forced stirring means 68, passes through the heat exchanger 69, and joins with the first circulation flow in the space between the heat insulating layer 61 and the inner cylinder 62. It circulates in the high-pressure container 60 with the circulation flow. In this way, the inside of the furnace chamber 66 is cooled.

Although not shown in the drawings, as another conventional technique, there is a technique disclosed in Japanese Utility Model Publication No. 62-24238. In this technique, a heat insulating layer includes an outer casing and an inner casing having an airtight structure. A gas passage is provided in the upper portion of the outer casing, and a valve for opening and closing the gas passage is provided. In this technique (conventional example 3), during the HIP process, the gas passage is closed by a valve to maintain the heat insulation effect inside the furnace, and after the HIP treatment, the gas passage is opened to open the gas between the outer casing and the inner casing. It has been attempted to shorten the cooling time in the furnace chamber by causing convection to cool the heat insulating layer by exchanging heat between the gas and the inner wall of the upper lid / container.

[0009]

In the HIP device according to the conventional example 1, the pressure medium gas is rapidly cooled at the start of circulation by heat removal by the heat storage body, but the temperature of the heat storage body rises, After the temperature of and the temperature of the pressure medium gas reach an equilibrium state, the heat storage body no longer cools the pressure medium gas, but rather radiates heat, which causes a problem that the cooling rate is extremely reduced. there were.

Further, in the conventional example 2 as a technique for improving this problem, since two forcing means for stirring the pressure medium gas are installed, not only the mechanism of the apparatus itself becomes complicated, but also the furnace There is a problem that the working volume in the room is significantly reduced. Furthermore, since there is only one pattern of the circulation path for the pressure medium gas, there is a problem that the cooling rate rapidly decreases as the furnace chamber becomes in an equilibrium state, and effective cooling of the furnace chamber cannot be performed. It was

Further, in the conventional example 3, the heat exchange between the inside of the furnace and the circulating gas flow is an indirect heat exchange through at least the inner casing, so that the cooling effect is significantly attenuated particularly in the latter half of the cooling process. There was a problem of doing. Therefore, it is an object of the present invention to provide a HIP device and a cooling method thereof, which enables rapid and effective cooling of a furnace chamber while ensuring an effective furnace interior volume ratio.

[0012]

According to the present invention, at least the inner and outer casings 11 and 12 and the both casings 11 and 12 have an inverted cup shape inside the high-pressure container 2 and have a through hole 10 in the upper portion.
Between the lower part and the upper part, a heat insulating layer 5 that allows gas to flow is provided, and the inside of the heat insulating layer 5 serves as a furnace chamber 6, and the through hole 10
In order to achieve the above-mentioned object, a hot isotropic pressure pressurizing device is provided with a first valve means (14) for opening and closing, and applying a high-temperature and high-pressure pressure medium gas to an object (8) in the furnace chamber (6). To
The following technical measures were taken.

That is, in the present invention, gas passage holes 15 and 16 for communicating the inside and outside of the furnace chamber 6 are provided in the upper and lower portions of the inner casing 11 in the heat insulating layer 5, and at least one of the gas passage holes 15 and 16 is provided. Is provided with a second valve means 17 that can be opened and closed. With this configuration, the second valve means 17 is provided in the initial stage of cooling when the inside of the furnace is in a relatively high temperature state. By opening only the first valve means 14 in the closed state, the pressure medium gas is circulated in a flow of raising the inside of the heat insulating layer 5 and lowering the space between the heat insulating layer 5 and the high pressure container 2. Cool down.

In this initial stage of cooling, the temperature in the furnace is sufficiently high, and at this time, the cooling rate is also correspondingly high, while the circulating gas flow for heat exchange with the inner wall of the high-pressure vessel 2 is the gas in the furnace. Since the temperature is lower than the temperature, it is possible to prevent the temperature of the container 2 from rising excessively.
Not only by opening the second valve means 17,
The gas itself in the furnace is circulated to accelerate the cooling (Claim 1).

Further, the present invention is characterized in that radiant heat blocking means 20 for the first valve means 14 is provided between the first valve means 14 and the furnace chamber 6, and as described above. With this structure, the radiant heat from the high temperature part in the furnace to the first valve means 14 is cut, the deformation of the valve is prevented, and the durability is ensured (claim 2). Further, the present invention is characterized in that the furnace chamber soaking means 19 is provided in the lower part of the furnace chamber 6, and with such a configuration, the treatment target due to the temperature difference between the upper and lower sides during rapid cooling is provided. Definitely prevent cracking of the object, nonuniformity of the structure, etc. (Claim 3).

In the cooling method according to the present invention, in the first half of the cooling process, the pressure medium gas is circulated in a flow that rises in the heat insulating layer 5 and descends in the space between the heat insulating layer 5 and the high pressure container 2, In the latter half of the cooling process, the pressure medium gas is circulated in a flow of rising in the furnace chamber 6 and descending in the space between the heat insulating layer 5 and the high-pressure container 2, as described above. By using two cooling modes, rapid and efficient cooling of the furnace chamber 6 can be realized not only in the first half of the cooling process but also after the furnace chamber 6 approaches the equilibrium state. The cycle can be shortened, the work efficiency can be improved as a whole, and the furnace chamber effective volume ratio can be sufficiently secured (claim 4).

Further, the cooling method according to the present invention is characterized in that the pressure medium gas is further circulated in the convection flow in the furnace chamber 6 throughout the first half and the second half of the cooling process. This ensures rapid cooling by reliably preventing cracks and the like in the object to be treated (Claim 5).

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of the present invention will be described with reference to the drawings. FIG. 1 and FIG. 2 show a first embodiment of the present invention, and FIG.
FIG. 2 shows the second half of the cooling process. 1 and 2, in a hot isotropic pressure pressurizing device 1, an upper lid 3 and a lower lid 4 are airtightly fitted into upper and lower openings of a cylindrical high-pressure container 2 through sealing means (not shown). Have been combined.

Inside the high-pressure vessel 2, an inverted cup-shaped heat insulating layer 5 is provided, and a space surrounded by the heat insulating layer 5 is a furnace chamber 6, and a support base 7 is interposed in the furnace chamber 6. The object 8 to be processed is installed inside, and the object 8 to be processed is subjected to the HIP process by operating the pressure medium gas such as Ar gas introduced into the furnace chamber 6 and the pressure medium gas of high temperature and high pressure in cooperation with the heater 9. Is possible.

The heat insulating layer 5 has a through hole 10 in the upper portion thereof, and at least the inner and outer casings 11 and 12 and the both casings 11 and 12.
Gas is allowed to flow from the lower part to the upper part between the outer casings 12. In the present embodiment, the outer casing 12 is made of metal in principle and has an airtight structure, while the inner casing 11 has an airtight structure. The inner and outer casings 11, 12 are made of stainless steel, nickel alloy, molybdenum, graphite, etc. according to the temperature conditions.
A necessary heat insulating performance is secured by filling a heat insulating material 13 such as a graphite material or ceramic fiber in the space.

The through hole 10 formed in the upper part of the heat insulating layer 5 can be opened and closed by the first valve means 14, and the first valve means 1
4 is a telescopic cylinder 14A attached to the upper lid 3,
It is composed of a poppet valve 14B attached to the piston rod. The inner casing 11 of the heat insulating layer 5 is formed with gas circulation holes 15 and 16 at the upper and lower portions thereof so as to communicate the inside and outside of the furnace chamber 6, and at least one of the gas circulation holes 15 and 16 is provided in the present embodiment. In addition, a second valve means 17 for opening and closing the lower gas flow hole 16 is provided, and the second valve means 17 is composed of a driving body 17A such as an electric motor and an electric cylinder and a valve portion 17B.

In the HIP apparatus 1 shown in FIGS. 1 and 2, the furnace chamber 6 is degassed and then the pressure medium gas is introduced, and the first and second valve means 14 and 17 are both closed. HIP is made by applying a high-temperature and high-pressure pressure medium gas to the processed material 8.
After the HIP process, the cooling process is performed.
The flow of the pressure medium gas in the first half of the cooling process (first half of the cooling process) after the HIP process will be described with reference to FIG.

After the HIP process, when the cooling of the furnace chamber 6 is started, if the first valve means 14 is opened, the inside of the heat insulating layer 5 rises due to natural convection due to the density difference of the pressure medium gas inside and outside the furnace chamber 6. Contact the upper lid 3 through the through hole 10 and circulate the space between the outer casing 12 and the inner surface of the high-pressure container 2 in the heat insulating layer 5 in a descending flow to contact the upper lid 3.
The heat is removed by contact with the inner surface of the high-pressure vessel 2 and the mode A is cooled.

In this mode A, the cooling rate is correspondingly high while the temperature in the furnace is high, while the circulating gas flow A1 that exchanges heat with the upper lid 3 and the high-pressure vessel 2 is lower than the gas temperature in the furnace. Therefore, the container 2 and the like are not overheated. However, as the cooling progresses over time, the inside and outside of the furnace chamber 6 approaches an equilibrium state, and the cooling rate decreases. Cooling in mode A alone results in cooling in accordance with the solid line B1 in FIG. 3 and the cooling time becomes longer. .

Therefore, the flow of the pressure medium gas is changed to prevent the cooling rate from decreasing. That is, as shown in FIG. 2, in the latter half of the cooling process (the latter half of the cooling process) in which the inside and outside of the furnace chamber 6 approach the equilibrium state, when the second valve means 17, which has been closed until now, is opened, the pressure medium gas is transferred to the furnace chamber 6 Mode B (circulating gas flow A2) is circulated by a flow that rises inside and descends the space between the heat insulating layer 5 and the inner surface of the high-pressure container 2, and the cooling rate is accelerated as shown by the broken line B in FIG. It is.

4 and 5 show a second embodiment of the present invention, in which the pressure medium gas is circulated by a gas flow C forcibly convection in the furnace chamber 6 in the first half and the second half of the cooling process. Since the basic configuration is the same as that of the above-described embodiment (FIGS. 1 and 2), common parts are denoted by common reference numerals, and differences will be described below. A large number of not-illustrated through holes are formed in the support base 7 in the vertical direction, and an inner cylinder 18 is provided on the support base 7 so as to surround an object to be processed (not shown).

Further, a furnace chamber soaking means 19 is provided below the supporting table 7 in the lower part of the furnace chamber 6, and the means 19 is provided.
Is an electric motor 19A and a fan 1 rotated by the electric motor 19A
It is composed of 9B. The heat insulating layer 5 includes an inner heat insulating layer 5A and an outer heat insulating layer 5B. The inner heat insulating layer 5A is supported by the ring body 4A of the lower lid 4, and the outer heat insulating layer 5B attaches the hanger 3A to the upper lid 3. Is supported through
A gas flow path 5C is formed between both heat insulating layers 5A and 5B.

In the HIP device shown in FIGS. 4 and 5, in the first half of the cooling process after the HIP process, the first valve means 14 is opened as shown in FIG.
By operating the circulating gas flow A1
Since a gas flow A3 for convection is generated in the inside, cracks in the object to be processed, nonuniformity of the structure and the like caused by the temperature difference between the upper and lower sides are eliminated, and the gas flow A3 is continued even in the latter half of the cooling process.

FIG. 6 shows another embodiment of the present invention, which is shown in FIG.
And in the HIP device 1 shown in FIG. 5, the first valve means 1
It is intended to prevent the thermal deformation of the first valve means 14 by prolonging the service life of the parts by providing the means 20 for shutting off the radiant heat to the No. 4 and the cooling step after the HIP treatment in the second embodiment. Is the same as. The radiant heat blocking means 20 is
The plate member 20A made of a heat-resistant material in the shape of an inverted dish is attached to the support tool 20.
It is attached to the inner heat insulating layer 5A via B.

Although the illustrated embodiment of the present invention is as described above, the following design changes are possible in the present invention. A second valve means 17 is also provided in the upper gas flow hole 15 so that it can be opened and closed. At this time, the lower gas flow hole 1
Whether or not to provide the second valve means 17 in 6 is arbitrary.

In the above-described first embodiment (FIGS. 1 and 2), the soaking means 19 or the radiant heat blocking means 20 is provided. In the case of a small high-pressure container, the container should be composed of a bottomed cylindrical main body and a lid that closes the opening. Provide a water cooling jacket on the outer wall of the high-pressure container to further increase the cooling speed of the pressure medium gas and improve work efficiency.

Providing flow rate control means for changing the rotation speed of the fan. And so on.

[0033]

As described in detail above, according to the present invention, the cooling time can be shortened and the productivity can be improved while sufficiently securing the effective volume ratio.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a first half of a cooling process according to the first embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing the first embodiment of the present invention in the latter half of the cooling process.

FIG. 3 is a comparison graph of cooling time between a conventional example and the present invention.

FIG. 4 is a vertical cross-sectional view of the first half of the cooling process according to the second embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view showing the second embodiment of the present invention in the latter half of the cooling process.

FIG. 6 shows a third embodiment of the present invention and is a vertical cross-sectional view during HIP processing.

FIG. 7 is a conceptual diagram of a conventional example 1.

FIG. 8 is a second conceptual diagram of a conventional example.

[Explanation of symbols]

 1 Hot Isostatic Pressurizing Device 2 High Pressure Container 5 Heat Insulation Layer 6 Furnace Chamber 10 Through Hole 14 First Valve Means 15 Gas Flow Hole 16 Gas Flow Hole 17 Second Valve Means

Claims (5)

[Claims] 1. A high-pressure vessel (2) having an inverted cup shape and a through-hole (10) in the upper part, and at least between the inner and outer casings (11, 12) and the both casings (11, 12) from the lower part. A heat insulating layer (5) that allows gas to flow toward the upper part is provided, and the inside of the heat insulating layer (5) is a furnace chamber (6),
First valve means (14) for opening and closing the through hole (10)
A hot isostatic pressurization device that applies a high-temperature and high-pressure pressure medium gas to an object to be treated (8) in the furnace chamber (6), the inner casing (11) of the heat insulating layer (5) Gas flow holes (15) and (16) communicating with the inside and outside of the furnace chamber (6) are provided in the upper and lower parts, and the gas flow holes (15) and (1) are provided.
Second valve means (1) for opening and closing at least one of (6)
7) A hot isostatic pressurizing device comprising: 2. Radiant heat blocking means (20) for the first valve means (14) is provided between the first valve means (14) and the furnace chamber (6). The hot isostatic pressurizing device described in. 3. The hot isostatic pressing device according to claim 1, wherein a furnace chamber soaking means (19) is provided in a lower portion of the furnace chamber (6). 4. A heat insulating layer (5) having a layered gas-flowable structure is provided in a high-pressure vessel (2), and a space surrounded by the heat insulating layer (5) is a furnace chamber (6). After the hot isostatic pressing process is performed by applying a high-temperature and high-pressure pressure medium gas to the object to be processed (8) in the furnace chamber (6) by the isostatic pressing device (1). In the cooling method of the hot isostatic pressurizing device (1), in which the pressure medium gas is circulated in the high pressure vessel (2) to cool the inside of the furnace chamber (6), in the first half of the cooling process, the pressure is increased. The medium gas is circulated in a flow that rises inside the heat insulating layer (5) and descends in the space between the heat insulating layer (5) and the high-pressure vessel (2), and in the latter half of the cooling process, the pressure medium gas is used in the furnace chamber ( 6) A method of cooling a hot isostatic pressurizing device, characterized in that the space between the heat insulation layer (5) and the high pressure vessel (2) is circulated in a descending flow ascending in the space. Law. 5. The hot isostatic pressurization apparatus according to claim 4, wherein the pressure medium gas is circulated in a convection flow in the furnace chamber (6) throughout the first half and the second half of the cooling process. Cooling method.