Manufacturing via Hot Isostatic Pressing
Powders to be compacted are placed inside a container or mold, usually made from mild steel and commonly called a capsule. Capsules can vary from simple shapes or preforms to highly complex near net shapes. A suitable evacuation connection is also welded on to the capsule and may double for powder filling purposes.
Evacuation and outgassing of the powder is accomplished by connecting a vacuum pump to an evacuation connection extended to reach outside the optional bakeout furnace. The container is pumped down until a level of at least 1,000 microns (1 Torr) is reached, then the temperature is brought up to 400°F–800°F (200°C–425°C) to remove adsorbed moisture. Vacuum pumping continues upon heating until the 1,000 micron (1 Torr) level is again reached inside the capsule. The connection tube is crimped close to the can while still under vacuum. The excess tube length is trimmed off to permit efficient loading into the hot isostatic press then weld overlaid. These two steps can be done independently of the HIP unit so loads can be prepared in advance and stockpiled.
Would you like to learn more about manufacuring via hot isostatic pressing? Watch these videos on powder metallurgy and isostatic pressing.
