Isostatic Pressing of Metallic Powders

Isostatic Pressing of Metallic Powders

Isostatic pressing is the powder compaction method involving applying pressure from multiple directions through a liquid or gaseous medium surrounding the compacted part.

Cold isostatic pressing (CIP) is conducted at room temperature.

A flexible (commonly polyurethane) mold immersed in a pressurized liquid medium (commonly water) is used in the cold isostatic pressing method.

There are two types of cold isostatic pressing: wet bag and dry bag.

In the wet bag method the mold is removed and refilled after each pressure cycle. This method is suitable for compaction of large and complicated parts.

In the dry bag method the mold is an integral part of the vessel. The dry bag method is used for compaction of simpler and smaller parts.

The cold isostatic pressing (CIP) method has the following advantages as compared to the die cold pressing method:

1. Better uniformity of compaction;

2. More complex forms (for example long thin-walled tubes) may be compacted;

3. Hot isostatic pressing (HIP) involves isostatic pressing conducted at increased temperature.

4. As a pressure medium a gas (Nitrogen or Argon) is used.