JPS6123703A - Hermetic type airtight vessel for hot hydrostatic pressurization treatment - Google Patents

Abstract

PURPOSE:To evacuate the inside of a vessel for a hot hydrostatic pressurization treatment with high reliability by attaching a specially constructed hermtetic sealing valve to the discharge port of said vessel and connecting the same to a vacuum evacuation device. CONSTITUTION:The discharge port 13 of the vessel 1 for a material (b) to be treted for use in the stage of pressurization and sintering by hot hydrostatic pressure and the discharge pipe 3 of the vacuum evacuation device 5 are connected by the hermetic sealing valve 10 consisting of a seal ring 12, a seal bearing 14 and a nut 11 fixing the same. The air in the vessel 1 is evacuated through the spacings between the valve seat 13a on the port 13 side and the bearing 14 and between the valve seat 3b on the pipe 3 side and the bearing 14 in the stage of eveacuating the inside of the vessel 1 by the device 5. The nut 11 is screwed down and is tightened to shut off the ventilation of the port 13 and the pipe 3 by the bearing 14 upon completion of the evacuation, by which the vessel 1 is thoroughly hermetically sealed from the outdoor air with high reliability.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to hot isostatic pressure processing in which powder such as metal powder, that is, a workpiece is compressed and sintered by simultaneously applying temperature and gas pressure. , relates to a sealed airtight container for accommodating the object to be processed.

[Conventional technology]

Hot isostatic pressing is already being applied by tool manufacturers to improve internal defects in cemented carbide tools, etc., and its track record is increasing. Isolated holes inside parts, such as internal defects in tools, can be crushed and crimped by applying gas pressure directly, but it is not possible to create an opening on the outer surface of the workpiece. The pores cannot be crushed by hot isostatic pressure treatment in which gas pressure is directly applied. Similarly, if gas pressure is applied directly to a powder compact made by compacting powder, although the pressure has the effect of compressing the powder particles themselves, it does not consolidate or densify the powder compact. Therefore, the effect of the original hot isostatic pressure treatment cannot be expected.

As mentioned above, 0), a workpiece that has holes with openings on its outer surface, (b), a green compact or an incomplete sintered body (
When processing a workpiece that cannot be directly applied with gas pressure, such as when the pores are not isolated, the workpiece must be heated so that hot isostatic pressure can be applied. Sealed, airtight containers are used to store items.

As shown in FIG. 4, the conventional sealed airtight container is filled with powder (b)'e to be treated, and then the airtight container (α)
The residual air inside is evacuated by a vacuum pump (d) through an exhaust pipe (C) and sealed, and subjected to hot isostatic pressure treatment.

Generally, in hot isostatic pressing using the airtight container (α), in order to ensure the properties of the material after sintering, residual air in the airtight container (α) is degassed to prevent oxidation. It is said that

After the residual air in the sealed airtight container (α) has been degassed, the vacuum pump (d) is operated on the part of the exhaust pipe (C) near the airtight container (α) as shown in Figure 5. In the on-line state, the exhaust pipe (C) is sealed by crushing and crimping (e), and the exhaust pipe (C) is cut at the top of the crimping (-), and the cut part is welded to form a sealing plug ω, and then subjected to hot isostatic pressure treatment. was carried out, and the state before the hot isostatic pressure treatment shown on the left side of Figure 6 changed to the state shown on the right side after the treatment, and the powder was deformed due to compaction of the powder and shrinkage due to sintering. Airtight container (α,
It becomes a sintered body (h').

[Problems with conventional technology]

In the conventional sealed airtight container, the inside of the container is degassed through an exhaust pipe connected to the airtight container, and then the exhaust pipe is crushed and crimped. It is uncertain and has low reliability, and there is a risk that air may flow back into the container from the peeled part of the crimped part during the period between cutting the exhaust pipe and welding the cut part, and even during welding. In addition, hot isostatic pressure treatment requires at least 8 hours of warming in one cycle in the case of large-scale equipment, and the objects to be treated are often made of expensive materials, so the above-mentioned troubles can be avoided. There are drawbacks such as the fact that it will result in very large losses.

[Purpose of invention, means for solving problems]

The present invention was developed in order to eliminate the above-mentioned conventional drawbacks, and the present invention has been developed by providing a structure in which an exhaust pipe connected to a vacuum evacuation device is connected to an exhaust port of a sealed airtight container and can be freely closed. It is characterized by a structure in which the airtight container is connected through a sealing valve, and the exhaust port of the sealed airtight container and the exhaust pipe connected to the vacuum exhaust device are connected through a sealing valve that can be freely closed and communicated with each other. The present invention provides a sealed airtight container for hot isostatic pressurization that eliminates the above-mentioned conventional drawbacks by significantly improving the operability of degassing the airtight container, as well as the sealing performance and reliability of the container. It is in.

[Embodiments of the invention]

An embodiment of the present invention is shown in FIGS. 1 to 3.
In Figure 1 (A), (1) in the figure indicates the object to be processed such as powder (
(+31 is an exhaust port of the sealed airtight container (1), (3) is an exhaust pipe, and the exhaust pipe (3) is a vacuum pump, that is, a vacuum exhaust device). (5)
The exhaust pipe (3) is connected to the exhaust port part α.
) are connected through a sealing valve Ql that can be freely closed and communicated with.

Furthermore, to describe the sealing valve HK in detail, as shown in the first drawing, the nut αυ is prevented from coming out by the 7-rank part (3α) of the exhaust pipe (3) and is rotatably fitted into the exhaust pipe (3). , a seal ring a disposed within the nut αυ
2. A cone-shaped valve seat (1st section) formed on the upper end surface of the exhaust port Q4, which is fixed by welding on the upper part of the sealed airtight container (1), and a cone-shaped valve seat (1st section) formed on the 7th rank section (3α). cone-shaped valve seat (3b), said valve seat (13α) and (3b)
A sealing valve aI is constructed by screwing a seal bearing αa, etc. υ and a nut aυ accommodated in between into the exhaust port Q3, and a sealed airtight container (11 side The exhaust pipe (3) is connected to the exhaust port a3 of the exhaust port a3 as shown in FIG.
When the screw is screwed forward and tightened, the seal Q4 is held between the valve seats (13a) and (3b), and the ventilation can be shut off or closed from the communication state.

Furthermore, as shown in Fig. 3, with the sealed valve part closed and the sealed airtight container (i+) sealed, the exhaust pipe (3) is cut, and the exhaust pipe (3) is cut between the exhaust port part (1:l and nut a1). At the same time, seal weld (18't-) between the exhaust pipe (3) and the cut part a
If plug 4 is fitted to e and a seal is welded between the two, the seal valve a can be formed into a seal plug integrated with the exhaust valve.

[Effect]

Since the embodiment of the present invention has the above-mentioned configuration, the residual air in the sealed airtight container (1) can be removed by loosening the tightening of the nut αD as shown in Fig. 1. The valve seat (13α) on the exhaust port a3 side, the seal earring α4, and the valve seat (3h) on the exhaust pipe (3) side
A gap is formed between the seal bearing Q4) and the seal bearing Q4), and the remaining air in the sealed airtight container (11) is discharged through the sealing valve Q(1) and the exhaust pipe (3), facing the exhaust port. It is evacuated and degassed by a continuous vacuum pump (5), that is, a vacuum evacuation device.

During this time, the gap between the end of the exhaust pipe (3) and the oak (11) and between the exhaust port Q3 and the nut 09 are sealed with seal ring α2, completely blocking the outside of the exhaust pipe from the exhaust pipe system. .

When the vacuum degassing is completed, screw the Nara H1 (with the vacuum evacuation device in operation) and tighten it to the state shown in Figure 2, and connect the seal bearing I between the exhaust port ([3] and the exhaust pipe (3)). The sealed airtight container (1) is sealed by closing, that is, blocking ventilation.

In this state, the seal bearing A4 is held between the valve seat (3h) on the exhaust pipe (3) side and the valve seat (13a) on the side facing the exhaust port, and the upper and lower surfaces of the seal bearing Q4) are in line contact. Therefore, the exhaust system can be completely sealed from the outside air. At this time, the seal ring θ2 deforms by the amount of tightening of the nut to cope with the problem, so it does not become an obstacle.

When actually subjecting the sealed airtight container (II) to hot isostatic pressure treatment, the seal may break due to thermal deformation during the treatment, so the state in which only the nut α1 is tightened (the (Fig. 2) has low reliability, so it is recommended to fit a plug and weld seals between each part as shown in Fig. 3, and to use a sealing plug integrated on the exhaust port side rather than a trap. , and reliability is significantly improved.

[Specific examples of implementation]

The metal powder (N: super heat-resistant alloy) was sintered using the sealed airtight container (11). After filling the container, the container was degassed for 10 hours using a vacuum pump to bring the vacuum inside the container to about 140'' Torr, and after tightening the sealing valve, the exhaust pipe was cut, and each part of the sealing valve was sealed and welded. The container (1) thus prepared was heated to a temperature of 1250°C.
The sintered body was then held in an atmosphere with a pressure of 2,000 yen for 2 hours to perform hot isostatic pressing (capsule sintering), and a sintered body of good quality was obtained.

[Effects of the Invention] 1. As mentioned above, the present invention connects the exhaust pipe connected to the vacuum evacuation device to the exhaust port of the sealed airtight container via a sealing valve that can communicate and close freely. Therefore, by tightening the sealing valve, communication and closure between the airtight container and the inside and the exhaust pipe can be made extremely easy, and even if the exhaust pipe is cut after the inside of the container is degassed, the airtightness of the container is ensured. In addition to significantly increasing its reliability, it is also extremely easy to plug and weld the sealing valve into a sealing plug that is integrated into the exhaust port side, and during hot isostatic pressure processing. It also ensures airtightness, improves hot isostatic pressing performance and reliability, and produces excellent processed products with no variations.

In addition, according to the embodiment, since the seal bearing is sandwiched between the valve seat on the exhaust port side and the valve seat on the exhaust pipe side and makes line contact with both valve seats, the sealing performance of the sealed airtight container is improved. is significantly increased.

Although the present invention has been described above with reference to embodiments, it goes without saying that the present invention is not limited to such embodiments, and that various design modifications can be made without departing from the spirit of the present invention. .

[Brief explanation of drawings]

FIG. 1(A) is an overall side view showing an embodiment of the present invention in partial cross section, FIG. 1(B) is an enlarged vertical cross-sectional view of the sealing valve of FIG. 1, and FIG. 2 is an enlarged longitudinal sectional view of the sealing valve of FIG. 3 is a vertical sectional view showing the state in which the sealing valve is equipped with a sealing means, and FIG. 4 is a partial sectional view of a conventional example [also a side view of the whole, Fifth
The figure is a longitudinal sectional view showing the crimped and sealed state of the exhaust valve, and FIG. 6 is a longitudinal sectional view showing the state of the sealed airtight container after pre-treatment. 1: Sealed airtight container 3: Exhaust pipe 5: Vacuum exhaust device (vacuum pump) 10: Sealing valve 13: Exhaust port sub-agent Patent attorney Shige Okamoto 3 outsiders Figure 2 Figure 3

Claims (1)

[Claims] A sealed type for hot isostatic pressure treatment, characterized in that an exhaust pipe connected to a vacuum evacuation device is connected to the exhaust port of the sealed airtight container via a sealing valve that can be freely closed and communicated with. Airtight container.