JPH0610283B2 - Method and device for confirming capsule integrity during hot isostatic pressing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is applied to the case where a metal or ceramic material is isotropically compressed and densified by hot isostatic pressing (hereinafter abbreviated as HIP) treatment. The present invention relates to a method and apparatus for confirming abnormality or soundness of a metal capsule enclosing a material to be processed.

(Prior Art) In recent years, for example, powder raw materials of metals or ceramics are filled in a container made of a metal material called a capsule and sealed, and a gas pressure is applied from the surroundings at high temperature to perform isotropic compression to achieve a high density. The HIP method of molding into a compact sintered body has been receiving attention and is rapidly spreading.

In the HIP method, maintaining the airtightness of the capsule containing the object to be treated with respect to the pressure medium gas is an essential condition for the purpose of the treatment.

In the HIP processing, usually, the object to be processed contained in the metallic capsule is loaded into the HIP processing device,
The HIP process is performed with a pressure medium gas such as argon gas or nitrogen gas. The pressure medium gas after the treatment is usually recovered by a gas recovery device and reused.

(Problems to be Solved by the Invention) However, if the hermeticity of the capsule is impaired for some reason during the HIP process, the HIP process of the object to be processed will fail.

Therefore, as a result of various studies on the method for detecting an abnormality of the capsule during the HIP treatment, the present inventors have found that the applicant has previously proposed a high-temperature and high-pressure molding and sintering method, that is, a method proposed by JP-A-51-88503. When the processing body is enclosed in a capsule and a HIP process is performed by causing a pressure medium gas to act in the high-pressure container, an adjusting pipe is provided which communicates with the inside of the capsule and whose end extends to the outside of the high-pressure container. The inventors have found that it is most suitable to apply the method of heating and pressurizing the object to be processed while adjusting the type and / or pressure of the atmospheric gas in the capsule, and arrived at the present invention.

That is, the present invention is to break the capsule during the HIP process,
The purpose is to detect abnormalities such as pinholes promptly and prevent inconvenience.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides a pipe system communicating from the inside of a capsule accommodating an object to be treated with the atmosphere, and a leak installed in the middle of the pipe system. Leakage of pressure medium gas is detected by a gas detector and / or pressure gauge to confirm the soundness of the capsule during HIP processing. First, the feature of the method of the present invention is that the object to be processed is a metal capsule. When the HIP treatment is performed by enclosing it in a high pressure vessel, inserting it in the high pressure vessel, and isothermally compressing it with a pressure medium gas while heating in the high pressure vessel,
The inside of the capsule is communicated with the outside of the high-pressure container by an atmosphere adjusting pipe line that is airtightly independent from the pressure medium gas, and the presence or absence of leakage of the pressure medium gas into the capsule is detected through a meter in the middle of the atmosphere adjusting pipe line. .

The apparatus used in such a method includes a high-pressure container consisting of a pressure-resistant cylinder and upper and lower lids thereof, a furnace chamber defined by a heating element disposed in the high-pressure container via a heat insulating layer, It consists of an atmosphere adjusting conduit that communicates with the inside of the metal capsule that is placed in the furnace chamber and that is kept airtightly independent of the atmosphere inside the furnace chamber and whose end extends to the outside of the high-pressure container, and the pressure medium gas is pressurized to a high pressure. In a HIP device comprising means for supplying into the container and means for heating a heating element, the atmosphere adjusting pipeline is connected to a detection pipeline communicating with a vacuum pressure gauge and a leak gas detector, and a vacuum pump is provided. It is configured so as to be openably and closably connected to a decompression pipe line that communicates therewith.

(Operation) According to the present invention described above, the object to be processed is stored in a capsule,
During HIP processing, if the capsule is damaged for some reason during processing and the processing gas leaks into the capsule from the furnace chamber, the leakage gas is guided to the leakage gas detection pipe through the atmosphere adjustment pipe, and the leakage gas detector Or it is detected by a pressure gauge.

Therefore, the HIP process is stopped by this detection, and the valve operation is performed, so that the subsequent scheduled process can be stopped.

(Examples) Hereinafter, specific embodiments of the method of the present invention will be described in detail together with examples of the apparatus.

FIG. 1 shows a cross-section and piping of a main body of a HIP apparatus suitable for carrying out the method according to the present invention and an object to be treated arranged therein.

In the figure, the high-pressure container is configured by a pressure-resistant cylinder (1) and an upper lid (2) and a lower lid (3) that close the upper and lower ends thereof, and each fitting portion is sealed by a sealing material (10) (10 '). It is kept airtight and the gas pressure acting on the lid is supported by a press frame (not shown). The heating element (4) (4 ') composed of an electric heating resistance wire supported by the supporting member (5) and the heat from these heating elements are used to heat and heat the object to be treated (13) inside the high-pressure container. Furnace chamber with built-in heat-insulating layer (6) that suppresses dissipation to the pressure-resistant cylinder (1), upper lid (2), and lower lid (3)
Define (7). Since the pressure medium gas is supplied to the high-pressure container through the pressure medium gas introduction hole (8), the pressure including the inert gas cylinder (26) such as nitrogen gas and argon gas, the compressor (25) and the shut-off valve (22). A medium gas introduction piping system (18) is additionally provided, and an electric supply circuit to the heating element is provided.

The object to be processed (13) is housed in a capsule (12) made of a metal material. An adjustment tube (14) is attached to the capsule (12), and this tube (14) communicates with a capsule internal atmosphere guide hole (11) provided in the lower lid (3) through a joint (15). As described above, it is detachable and connected to the pressure medium gas in the furnace chamber (7) by a seal ring (16) so as to maintain airtightness
(32) is formed.

The detection conduit (17) is connected to the atmosphere guide hole (11). This detection conduit (17) communicates with the vacuum pressure gauge (27) and the leak gas detector (29), respectively, and also with the decompression conduit (33) that communicates with the vacuum pump (24) for suction and exhaust in the capsule. Is openably and closably connected via a stop valve (20). Stop valve
(19) controls the opening and closing of the pipeline that leads to the atmosphere in the detection pipeline, the stop valve (21) controls the opening and closing of the decompression pipeline (33) to the atmosphere, and the safety valve (31) controls the detection pipeline ( It is a pressure release device for abnormally high pressure that acts in 17). Furthermore, a stop valve is installed in the detection line.
The pipeline connected via (19) branches into the pipeline leading to the gas treatment facility (30) and the pipeline communicating with the pressure medium gas introduction piping system (18) via the stop valve (23). .

Next, the operation will be described based on the above embodiment.
(13) is filled in a capsule (12) made of metal material,
The lid with the adjusting tube (14) is welded to the capsule.

The object to be treated (13) housed in the capsule (12) is fixed on the pedestal (9) in the furnace chamber (7) as shown in FIG.
Is hermetically connected to the atmosphere guide hole (11) by the joint (15) to form an independent atmosphere adjusting pipe (32). .

Here, if it is necessary to evacuate the inside of the capsule, open the stop valve (20) with the stop valve (19) (21) closed,
The vacuum pump (24) in the depressurizing pipe line (33) is operated and exhausted. After evacuation, close the stop valve (20) and open the stop valve (21) HIP
Prepare for processing. Then, if necessary, the gas cylinder (26),
Several to several tens of kgf / cm ² of pressure medium gas, pressure medium gas introduction hole (8) from pressure medium gas introduction piping system (18) consisting of compressor (25), stop valve (22) and pressure gauge (28) Then, the gas in the high-pressure vessel is replaced and cleaned by introducing and discharging it.

Next, the compressor (25) is operated, the pressure medium gas is filled in the high pressure container, and the temperature rise is gradually started. By maintaining a predetermined processing pressure and processing temperature for a certain period of time, the object to be processed (13) becomes HI.
P processing is performed. The pressure of the pressure medium gas is detected by a pressure gauge (28), and the temperature inside the furnace is detected by a thermocouple (not shown).

For some reason, the capsule (12) was damaged during the HIP process,
If the pressure medium gas leaks into the capsule from the furnace chamber (7),
The leaked gas is guided to the detection pipe line (17) through the adjustment pipe (14) and the atmosphere guide hole (11) and detected by the leaked gas detector (29) or the vacuum pressure gauge (27).

After detection, the stop valve (22) is closed and the supply of pressure medium gas is stopped, and at the same time the stop valve (19) is opened and the leak gas is guided to the gas treatment facility (30) and removed, and the residual gas after removal is released to the atmosphere. To be done.

On the other hand, the gas in the high-pressure container is also led to the gas treatment facility (30) by opening the stop valve (23), treated in the same manner as the leaked gas, and released to the atmosphere.

The presence or absence of the leaked gas can be easily detected by first changing the indicated value of the vacuum pressure gauge (27).

That is, the atmosphere in the capsule depressurized by the operation of the vacuum pump (24) of the depressurizing conduit (33) slightly changes due to vaporization or expansion of the volatile components in the hull due to high temperature, but especially the capsule (12). When the pressure medium gas leaks into the capsule due to an abnormality in the pressure, the pressure rises rapidly.

When the pressure reaches a specified value, an alarm is issued and at the same time, a stop valve
It is preferable to provide an automatic control mechanism that opens the valve (19) and closes the stop valve (22).

In addition, in preparation for the possibility that the pressure in the detection pipe (17) has become abnormal due to some other cause, the presence or absence of the mixture of pressure medium gas is detected by the gas analysis value in the leak gas detector (29). To do. If no pressure medium gas is detected in the atmosphere inside the capsule (12), it is possible to avoid wasteful discharge and disposal of the pressure medium gas.

That is, it is most preferable to automatically or manually release the pressure medium gas due to the pressure abnormality, on condition that the leak gas detector (29) detects the gas.

(Advantages of the Invention) The present invention has the above-described configuration and action, and when the airtightness of the capsule is impaired during HIP treatment, it is immediately detected and prompt action is taken. Therefore, it is possible to confirm the airtightness and soundness of the capsule, which is an essential condition in the HIP process, and to immediately detect the abnormality, and by continuing the treatment for a long time while the capsule is abnormal, the cost of the expensive device can be reduced. It has a great economic effect of preventing a decrease in efficiency and a large loss of heat energy.

[Brief description of drawings]

FIG. 1 is a schematic view showing a longitudinal section and a piping system of a main body portion of a device of the present invention and an object to be treated arranged therein. (1) …… Pressure-proof cylinder, (2) …… Upper lid, (3) …… Lower lid, (4) …… Heating element, (6) …… Insulation layer, (7) …… Furnace chamber, (8) ...... Pressure medium gas introduction hole, (17) …… Detection pipe, (18) …… Pressure medium gas introduction piping system, (19) (20) (21) (22) (23) …… Stop valve, (24) …… Vacuum pump, (27) …… Vacuum pressure gauge, (29) …… Leakage gas detector, (30) …… Gas treatment equipment, (32) …… Atmosphere adjusting line, (33)… … Depressurization line,

Claims (5)

[Claims] 1. A capsule for encapsulating an object to be treated in a metal capsule and inserting it into a high-pressure container, and performing isotropic compression with a pressure medium gas while heating in the high-pressure container to perform hot isostatic pressing. The inside is made to communicate with the outside of the high-pressure container by an atmosphere adjusting pipe line that is airtightly independent from the pressure medium gas, and the presence or absence of leakage of the pressure medium gas into the capsule is detected through a meter in the middle of the atmosphere adjusting pipe line. How to check the integrity of capsules during hot isostatic pressing. 2. The capsule at the time of hot isostatic pressing according to claim 1, wherein the detection is performed by a pressure change of a decompressed atmosphere formed by sucking and degassing the inside of the capsule through an atmosphere adjusting pipe line. How to check the soundness. 3. The method for confirming the soundness of a capsule at the time of hot isostatic pressing according to claim 2, wherein the detection is performed in combination with gas analysis. 4. A high-pressure container comprising a pressure-resistant cylinder and upper and lower lids thereof, a furnace chamber defined by a heating element disposed in the high-pressure container via a heat insulating layer, and disposed in the furnace chamber. A means for supplying a pressure medium gas into the high-pressure vessel, which comprises an atmosphere-adjusting conduit communicating with the inside of the metal capsule and keeping airtightly independent of the atmosphere in the furnace chamber and having an end extending outside the high-pressure vessel. In the hot isostatic pressing device comprising a heating means for heating the heating element, the atmosphere adjusting pipeline is connected to a detection pipeline communicating with the vacuum pressure gauge and the leak gas detector, and a decompression communicating with a vacuum pump is also provided. A device for confirming the integrity of a capsule during hot isostatic pressing, characterized by being connected to a pipeline for opening and closing. 5. The capsule for hot isostatic pressing according to claim 4, wherein the detection pipeline is further openably and closably connected to the inside of the gas processing facility and the inside of the high-pressure vessel via a stop valve. Soundness confirmation device.