JPS5810669B2 - Thermal insulation structure of heating chamber in high temperature and high static pressure equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in thermal insulation structures in high temperature, high static pressure equipment.

Processes materials such as cemented carbide, ceramics, ferrite, and superalloys at high temperatures and high static pressure to remove internal defects.
In recent years, so-called hot isostatic presses have been widely used industrially to improve the characteristics and reliability of products by increasing their density and diffusion bonding of dissimilar metals, oxides, etc. This is a time when it is becoming more and more popular.

The pressure medium in hot isostatic pressing is usually an inert gas such as argon, helium, nitrogen, etc., especially argon gas.

Although argon gas has a significantly large heat capacity at high temperatures and high pressures, its viscosity is not as large as that at atmospheric pressure, so it is known that it is extremely susceptible to convection phenomena at high temperatures and high pressures. .

Therefore, if the heating chamber of a high-temperature, high-static-pressure device is not reasonably thermally insulated from the outside of the heating chamber, heating may occur due to the convection phenomenon between the heating chamber of the pressure medium such as argon gas and the outside of the heating chamber (high-pressure chamber). Not only does efficiency decrease, but heat is released locally from areas with low thermal insulation capacity, increasing thermal distortion of the thermal insulation starting from those areas, which eventually leads to cracks and other damage, reaching the end of the product's lifespan. Repairs and updates may be required.

The outline of the hot press apparatus is as shown in the cross-sectional view of FIG. There is a heating chamber 8 surrounded by a heat insulating lid 6 on the chamber opening/closing side and a heat insulating part 7 on the fixed side of the heating chamber, and the high pressure chamber and the heating chamber are connected by a small gas hole 9 specially provided at one location around the periphery. , balances the pressure and prevents damage due to internal pressure.

The object to be processed 10 inserted through the heat insulating lid 6 on the opening/closing side of the heating chamber is
The heating element 12 connected to the heating power source 11 and the high pressure inert gas sent from the gas tank 15 through the high pressure gas compressor P1 gas valve 14 undergo high temperature and high static pressure treatment.

In the figure, 16 is a part into which a pressure seal gasket is inserted.

In the 4th part of FIG. 1, the conventional one has the structure shown in FIG. 2.

That is, the thermal insulator 1 is placed in the upper groove 51 of the heating chamber thermal insulator 5.
3, and above it a groove 51 with the lower surface of the heat insulating lid 6 convex.
In this case, the thermal insulating lid, especially 6 near the thermal insulating material 13, and the heating chamber thermal insulating material 5 have different coefficients of thermal expansion and different amounts of strain, so the thermal insulating material Distortion increases due to the heat release and gas release from this portion, which are effectively activated by the heat insulating lid 6, until the groove 51 and the protrusion on the heat insulating cover 6 cannot be separated from each other.

In order to prevent this distortion mechanically, bolt holes 52 made in the heat insulation cover 5 and bolt holes 53 made in the heat insulation cover 6 may be fixed with bolts 54 as shown in FIG. Strain following (structural parts that easily follow distortion such as thermal strain) 5
5 is applied to the thermal insulation film 5, the above problem still occurs.

As mentioned above, due to the increase in the size of the mold, cracks are generated at the welded parts of the heating chamber-side thermal insulator 5, and the cracks expand, reducing the thermal insulation capacity of the entire heating chamber and widening the temperature distribution. Conditions cannot be obtained and thermal insulation show 5
Furthermore, the heating element 12 may need to be repaired or replaced.

The present invention solves these problems and significantly improves the thermal insulation and the life of the heating element in high-temperature, high-static pressure equipment.
As shown in the figure, the lower surface of the heat insulating lid 6, that is, the surface facing the heat insulating cover 5 side, is made flat, and the heat insulating material 13 is inserted into the groove 51, so that the hot gas from the heating chamber 8 passes through the gap and exits the heating chamber. is preventing it from moving.

Only the thermal insulator 13 is interposed between the thermal insulation cover 6 and the thermal insulation plate 5, and the difference in strain is absorbed by the thermal insulation 13, and the thermal insulation plate 5 has a uniform thermal insulation capacity in the circumferential direction. It was designed to be kept.

The groove 51 fixes the thermal insulating material 13, and when the fibrous (square band-shaped) thermal insulating material 13 is pressed against it, it becomes clogged and becomes hard.
This makes it easy to increase the density of

Further, depending on the case, by tightening the heat insulating cover 6 and the heat insulating show 5 with bolts 54, the center positions of the heat insulating cover 6 and the heat insulating show 5 can be fixed, and the bolts 54 are applied at about 12 locations in the circumferential direction. Lightly tightening is sufficient.

As the thermal insulator in the present invention, ordinary materials are used, but in particular Al2O3+5102. It is preferable to use a fibrous insulator containing a high melting point element such as ZrO2 as a main component, such as asbestos felt (string).

The heat insulating lid 6 is composed of an outer frame container filled with alumina fiber, etc., and the heating chamber insulation cover 5 is made of a Mo cylinder on the inside and a stainless steel cylinder (filled with alumina fiber, etc.) on the outside. ).

As described above, in the present invention, an inert gas is used as a pressure medium, and 5
In a device that generates a high static pressure of 100 Kp/cm2 or more at a high temperature of 00°C or higher, the heating chamber at the opening/closing side end where the workpiece is taken in and out and the high pressure chamber are interposed only with a thermal insulator, resulting in good thermal insulation. This prevents convection of the inert gas to the outside of the heating chamber, thereby preventing thermal distortion of the device and further damage such as cracks.

As mentioned above, the present invention is particularly effective when applied to a high-temperature, high-static-pressure apparatus using a top loading method in which objects are taken in and taken out by opening and closing the earth part of a high-pressure tube or heating chamber, but it can be applied to any other method. It can also be applied to the thermal insulation structure of high temperature, high static pressure equipment.

Example Cemented carbide etc. at 1100-1450℃, 100-2000℃
Kg/cm7G, mainly 1000 Kp/cm2 or higher, for 30 to 60 minutes each, and then cooled. Asbestos was used as a thermal insulator to construct the structure of the present invention (Fig. 4) and the conventional structure (Fig. 2). )’s hot-breathing device (
The diameter of the groove 51 is φ450), and when compared, the strain development rate in the structure of the present invention is less than 1/35 of that in the conventional structure, and in the conventional structure, the show 5 and the lid 2 are removed in 4 to 10 cycles. On the other hand, the type of the present invention hardly becomes distorted even after 190 cycles.

In the present invention, only the thermal insulation 13 needs to be replaced approximately once every 10 cycles.

[Brief Description of the Drawings] Figure 1 is a cross-sectional view schematically showing the high temperature, high static pressure equipment, and Figures 2, 3, and 4 show the heat of the heating chamber and high pressure chamber of the high temperature, high static pressure equipment. FIGS. 2 and 3 are diagrams showing the insulating structure, and FIGS. 2 and 3 are the conventional ones, and FIG. 4 is the insulating structure of the present invention.

Claims (1)

[Scope of Claims] 1. A high-temperature, high-static-pressure apparatus using an inert gas as a pressure medium, characterized in that the heating chamber at the opening/closing end where the workpiece is taken in and out and the high-pressure chamber are interposed only by a thermal insulator. do,
Thermal insulation structure of the heating chamber in high temperature, high static pressure equipment. 2. A thermally insulating structure for a heating chamber in a high temperature, high static pressure apparatus according to claim 1, which uses a fibrous insulator containing a high melting point element as a main component as a thermal insulator. 3. A thermally insulating structure for a heating chamber in a high temperature, high static pressure apparatus according to claim 1, wherein a closing part for taking in and out the processed material is located in the upper part of the cylindrical high temperature, high static pressure apparatus. 4. In a high-temperature, high-static-pressure device that uses inert gas as a pressure medium, the heating chamber and the high-pressure chamber at the opening/closing end where the processed material is taken in and out are interposed only through a thermally insulating part, and the thermally insulating lid and one end of the high-pressure chamber are A thermal insulation structure for a heating chamber in a high temperature, high static pressure device, characterized by bolting in one circumferential direction.