HOT ISOSTATIC PRESSING METHOD AND APPARATUS

Abstract

A hot isostatic pressing method is disclosed wherein workpieces are accommodated within a high pressure vessel and the interior of the high pressure vessel is filled with an inert gas of a high temperature and a high pressure to treat the workpieces. The method includes a cooling step which is performed after maintaining the interior of the high pressure vessel at a high temperature and a high pressure for a predetermined time and in which a liquid inert gas is fed into the high pressure vessel. According to this method it is possible to shorten the cycle time of an HIP apparatus.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a hot isostatic pressing apparatus embodying the present invention;

FIG. 2 is a sectional front view of a high pressure vessel;

FIG. 3 is a flow chart of HIP treatment;

FIG. 4 is a diagram showing temperature and pressure changes in HIP treatment;

FIG. 5 is a diagram showing the motion of argon within the high pressure vessel in HIP treatment;

FIG. 6 is a diagram showing the motion of argon within the high pressure vessel in HIP treatment;

FIG. 7 is a diagram showing the motion of argon within the high pressure vessel in HIP treatment;

FIG. 8 is a diagram showing the motion of argon within the high pressure vessel in HIP treatment;

FIG. 9 is a sectional front view of a high pressure vessel in another embodiment of the present invention;

FIG. 10 is a diagram showing a drive mechanism for a cooling fan, the drive mechanism using pulleys and a belt;

FIG. 11 is a diagram showing the motion of argon within the high pressure vessel in HIP treatment;

FIG. 12 is a diagram showing the motion of argon within the high pressure vessel in HIP treatment;

FIG. 13 is a diagram showing the motion of argon within the high pressure vessel in HIP treatment;

FIG. 14 is a diagram showing the motion of argon within the high pressure vessel in HIP treatment;

FIG. 15 is a diagram showing the state of blast in a cooling fan;

FIG. 16 is a sectional front view of a high pressure vessel in a further embodiment of the present invention;

FIG. 17 is a sectional front view of a high pressure vessel in a still further embodiment of the present invention; and

FIG. 18 is a sectional front view of a conventional high pressure vessel.

Claims

1. A hot isostatic pressing method comprising the steps of: accommodating a workpiece in the interior of a high pressure vessel;filing the interior of said high pressure vessel with gas and maintaining the interior of said high pressure vessel at a high temperature and a high pressure for a predetermined time to treat said workpiece; andcooling said workpiece after the high temperature, high pressure treatment,wherein said cooling step includes a step of supplying liquefied gas into said high pressure vessel.

2. The hot isostatic pressing method according to claim 1, wherein said gas is an inert gas.

3. The hot isostatic pressing method according to claim 1, wherein said gas and said liquefied gas are the same substance.

4. The hot isostatic pressing method according to claim 1, wherein said cooling step includes a first step of cooling the workpiece without supplying said liquefied gas into said high pressure vessel and a second step of cooling the workpiece while supplying said liquefied gas into said high pressure vessel after said first step.

5. The hot isostatic pressing method according to claim 1, wherein, in said cooling step, a fan provided in the interior of said high pressure vessel is rotated to agitate the gas present within said high pressure vessel.

6. The hot isostatic pressing method according to claim 1, wherein the supply of said liquefied gas into said high pressure vessel is performed using a cryogenic pump.

7. A hot isostatic pressing apparatus comprising: a high pressure vessel for accommodating a workpiece therein and treating said workpiece with use of a high temperature, high pressure gas;gas supply means for supplying said gas into said high pressure vessel; andliquefied gas supply means for supplying liquefied gas into said high pressure vessel.

8. The hot isostatic pressing apparatus according to claim 7, wherein a passage for supplying said gas into said high pressure vessel and a passage for supplying said liquefied gas into said high pressure vessel are separate from each other.

9. The hot isostatic pressing apparatus according to claim 7, wherein a fan is provided within said high pressure vessel.

10. The hot isostatic pressing apparatus according to claim 9, wherein said high pressure vessel includes: an isolation chamber-forming member accommodated within said high pressure vessel in such a manner that an outer surface thereof is spaced from an inner surface of said high pressure vessel; anda treatment chamber-forming member accommodated within said isolation chamber-forming member in such a manner that an outer surface thereof is spaced from an inner surface of said isolation chamber-forming member,said isolation chamber-forming member being open at one of upper and lower ends thereof, or a passage for communication between the interior and the exterior of said isolation chamber-forming member being formed in the one end, and a passage for communication between the interior and the exterior of said isolation chamber-forming member and a valve for opening and closing said passage being provided in the other end, said treatment chamber-forming member being open at one of upper and lower ends thereof, or a passage for communication between the interior and the exterior of said treatment chamber-forming member being formed in the one end, and said fan is provided in the other end for ventilation.

11. The hot isostatic pressing apparatus according to claim 9, wherein said high pressure vessel includes: an isolation chamber-forming member accommodated within said high pressure vessel in such a manner that an outer surface thereof is spaced from an inner surface of said high pressure vessel; anda treatment chamber-forming member accommodated within said isolation chamber-forming member in such a manner that an outer surface thereof is spaced from an inner surface of said isolation chamber-forming member,said isolation chamber-forming member being open at one of upper and lower ends thereof, or a passage for communication between the interior and the exterior of said isolation chamber-forming member being formed in the one end, and a cooling fan being provided in the other end, said cooling fan being configured so that a flow direction is reversed by forward-reverse switching of a rotational direction of the fan,said treatment chamber-forming member being open at one of upper and lower ends thereof, or a passage for communication between the interior and the exterior of said treatment chamber-forming member being formed in the one end, and said fan is provided in the other end for ventilation.

12. The hot isostatic pressing apparatus according to claim 11, wherein said fan and said cooling fan are configured so that respective rotations can be controlled each independently.

13. The hot isostatic pressing apparatus according to claim 7, wherein said liquefied gas supply means is a cryogenic pump.