JPS5850237Y2 - Hot isostatic pressure treatment equipment - Google Patents

Description

[Detailed description of the invention] The present invention is a processing device that performs processing such as sintering by performing hot isostatic pressure treatment (hereinafter abbreviated as HIP) on a workpiece placed in a high-pressure container in a high-temperature, high-pressure gas atmosphere. It is especially suitable as a HIP treatment equipment for refractory materials such as silicon nitride, and it shortens the pressure increase time of the HIP cycle in high temperature HIP treatment and improves the operating economy by increasing the utilization efficiency of the compressor used for pressure increase. The present invention relates to a new HIP device that can be used.

The HIP method uses the synergistic effect of high hydrostatic pressure and high temperature to sinter powder materials, remove defects such as cavities remaining in cast products and powder sintered crystals, and densify them. It is known as an extremely effective method for diffusion bonding various materials, and has recently attracted attention as a sintering technique for ceramic materials in particular.

In conventional HIP apparatuses for powder metallurgy, the HIP temperature is generally up to about 1000°C, but in HIPing heat-resistant ceramics, a HIP temperature of about 2000°C is often required.

At such high temperatures, the influence of temperature on pressure increases, and the compressor for supplying pressurized gas has changed from a conventional two-stage compressor consisting of a low-pressure compressor and a high-pressure compressor to a low-pressure compressor alone. Although it has the advantage of being able to obtain a HIP pressure of
As is well known, in the P method, the object to be processed is processed in a high-temperature, high-pressure gas atmosphere formed in a high-pressure container, so it has to be a batch process, and moreover, during the HIP cycle time, the pressure medium gas is transferred to the high-pressure container. Since it takes a considerable amount of time to supply and recover the HIP, the HIP cycle time is inevitably long, and therefore the productivity is low. HI
Despite the advantages of P, this ceramic powder H
This is one of the major obstacles to putting IP processing into practical use.

Normally, HIP processing has a particularly large influence and effect on shortening the HIP cycle time, and one of the most important effects is shortening the time required for the initial pressure increase.

In this case, the gas used as the pressure medium in the HIP method is generally highly compressible, so to increase the pressure in a short time, an extremely large capacity compressor is required. Since the proportion of operating time of the compressor in one cycle is extremely small, an increase in equipment cost and running cost is unavoidable, and therefore increasing the capacity of the compressor is by no means a good idea.

On the other hand, in contrast to the above method, there is a method of installing many small-capacity compressors in parallel, but this not only increases the number of compressors used and complicates the equipment, but also makes it difficult to operate them in a coordinated manner. There were many problems, such as being quite troublesome.

In other words, in either method, the compressor operation period is limited to part of the supply and recovery of pressurized gas, and the compressor is stopped during the HIP process, which takes up more than half of the cycle. In reality, the operating rate was extremely low.

The purpose of this invention is to focus on the operating rate of the compressor and improve the efficiency of the HIP equipment by increasing it.In particular, the compressor is also used in the HIP process, which is the period when the conventional compressor is stopped. The purpose is to improve efficiency by operating and prolonging the operating period in the recovery process,
The feature is that in addition to the gas holder as a pressure medium gas supply source, the pressure vessel and compressor that performs HIP processing, an intermediate container is provided to intermediately store pressure medium gas, and during the HIP process period. Pressurized gas in the gas holder is pressurized by a compressor and stored in an intermediate container.When gas is supplied, the pressurized gas is directly supplied from the intermediate container to the high-pressure container, and when gas is recovered, it is stored in the high-pressure container. The main point is that each component device is connected in such a way that the gas is recovered using a compressor and at the same time stored in an intermediate container.

Note that the term "pressure gas" as used in the present invention includes a reaction gas such as nitrogen gas in reaction sintering of silicon, which is inert to the object to be processed, such as in normal sintering. I'm talking about gas.

The apparatus of the present invention will be described in detail below with reference to embodiments shown in the accompanying drawings.

In Figure 1, 1 is a high-pressure container, 2 is a force holder that is a source of pressure medium gas, 3 is a compressor, 4 is a pressure-resistant intermediate container, and 1 to V9 are connected to each line. 5 and 6 are the on-off valves provided, and 5 and 6 are the compressor 3 and the high pressure vessel 1.
and a bypass line connected to the compressor inlet side from the lines connecting the compressor and the intermediate container 4, respectively.

The HIP cycle in the device of the present invention having the above configuration will be explained in order of each step. First, the basic HIP process starts from eight steps S1 to S8 as shown in FIG.
Each step is as follows.

SL: Open the valves 6 to V9 to transfer the pressurized pressure medium gas in the intermediate container 4, for example, the pressure medium gas stored at a pressure approximately equal to the maximum discharge pressure of the compressor 3, to the object to be treated. An initial filling process in which the charged high-pressure container 1 is naturally fed using the difference.

S2: At the time when the internal pressures of the intermediate container 4 and the high pressure container 1 are approximately balanced, valve 7 is closed, and valve V4. v2. (2) A pressurized filling step in which the pressure medium gas in the intermediate container 4 is supplied under pressure to the high-pressure container 1 through the bypass line 6 and the compressor 3.

Ss: The internal pressure of the intermediate container 4 is a predetermined pressure, for example, the gas holder 2
At the stage when the internal pressure has decreased to , valve ■4. (1) Processing and filling step in which valve (1) is closed, valve (1) is opened, and the pressure medium gas in the gas holder (2) is pressurized and supplied to the high-pressure container (1) via the compressor (3).

S4: When the internal pressure of the high pressure container 1 reaches a predetermined pressure, the valve V6.
V9 is closed to stop the supply of pressure medium gas to the high-pressure vessel 1, and the interior of the high-pressure vessel 1 is maintained at high temperature and high pressure for a predetermined period of time to carry out the HIP treatment of the object to be treated. (2) An intermediate container storage step in which 8 is opened and during this time the pressure medium gas in the gas holder 2 is supplied to the intermediate container 4 via the compressor 3 and stored therein.

Note that when the internal pressure of the intermediate container 4 reaches a predetermined pressure, the compressor 1 is stopped and all valves are returned to closed positions.

S5: When the HIP treatment of the object to be processed in the high-pressure container 1 is completed, valves 6 to v9 are opened and the pressure medium gas in the high-pressure container 1 is recovered to the intermediate container 4 using the differential pressure.A natural recovery step.

S6: When the pressures in the intermediate container 4 and the high pressure container 1 are almost balanced, valve v6 is closed, and valve v3. (2) A step of opening 5 and forcibly recovering the pressure medium gas in the high-pressure container to the intermediate container 4 via the bypass line 5 and the compressor 3.

S7: When the pressure in the intermediate container 4 reaches the predetermined storage pressure, the valves Vs, V7. Close V8 and open valve ■1. ■Open 2,
A process of naturally recovering the pressure medium gas in the high-pressure container 1 to the gas holder 2 using differential pressure.

S8: When the pressures in the gas holder 2 and the high-pressure container 1 are almost balanced, valve V3 is closed and valve V3. V4. V5. Open V7 and transfer the remaining gas to gas holder 2, bypass line 5,
A process of forced recovery via the compressor 3 and bypass line 6.

Table 1 shows the valve operations and compressor operations in the above steps S1 to S8.

○ mark indicates operation/opening, no mark indicates stop/closed valve.

When the HIP cycle is completed as described above, the object to be processed is removed from the high-pressure container, the next object to be processed is loaded, and the process is repeated again.

In step S6, if forced recovery is performed until the residual pressure in the high-pressure vessel 1 approaches the pressure of the gas holder 2, step S7 is omitted and forced recovery is directly performed in step S8.

Here, it is desirable that the pressure increase time and the recovery time are approximately equal to each other, so it is necessary to determine the capacity of the offshore vessel 5 in consideration of the pressure holding time.

As described above, according to the device of the present invention, the compressor is operated even in the HIP processing step S4 when the compressor is stopped conventionally, and the pressure medium gas in the gas holder 2 is pressurized and stored in the intermediate container 4. In addition, even during gas recovery, the compressor 3 is operated to forcefully recover the gas into the intermediate container, so compared to the conventional method, the compression that is involved in the filling and recovery of pressure medium gas into the high-pressure container 1 is performed directly and indirectly. The operating rate of machine 3 will be increased, and the gas filling and recovery time will be significantly shortened.

That is, in the initial filling step S1, compared to filling the high-pressure container 1 from the conventional gas holder 2 using the differential pressure, filling is performed from the intermediate container 4 maintained at a high pressure, so that the high-pressure container 1 is filled in a shorter time and at higher pressure. In the recovery process, the compressor 3 can be used to collect both the intermediate container 4 and the gas holder 2, compared to the conventional case where only the gas holder 2 is recovered. Therefore, the HIP cycle time is greatly shortened, and at the same time, the operating rate of the HIP device is also greatly improved.

Incidentally, according to calculations, when operating a commercial P device continuously for 24 hours, the operating rate was 6 to 8 cycles with a conventional device that does not use an intermediate container, but with the device of the present invention, the operating rate is 16 to 20 cycles.
It is expected that this will greatly contribute to expanding the scope of application of HIP treatment, which will enable cycle operation.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of the device of the present invention, and FIG. 2 is a diagram showing pressure changes in each step of the HIP cycle of a high-pressure container, an intermediate container, and a gas holder. 1... High pressure container, 2... Gas holder, 3... Compressor, 4... Intermediate container.

Claims (1)

[Scope of utility model registration request] Gas holder 2 as a pressure medium gas supply source as an element equipment
and a hot isostatic pressure treatment apparatus comprising a high pressure container 1 and a compressor 3 for accommodating an object to be treated and subjecting it to hot isostatic pressure treatment,
In addition to the above-mentioned elemental equipment, an intermediate container 4 for intermediately storing pressure medium gas is provided, and the gas holder 2 and compressor 3 are connected in series, and the intermediate container 4 and high-pressure container 1 are connected in parallel to this. In addition to providing connecting lines, bypass lines 5 and 6 are connected to the compressor suction side from each line connecting the compressor 3 and the high-pressure container 1 and the compressor 3 and the intermediate container 4, respectively.
A hot isostatic pressure treatment device characterized by being provided with.