Cold Isostatic Pressing

Cold Isostatic Pressing is often used to press powder consiting of ceramics, plastics or other material together to a uniform form. Cold Isostatic Presses are often used in companies that produce for example casting for watches. Produces with an Cold Isostatic Press, the castings are normally safed against scratches and as a result, the whole watch looks like new even after amny years of use. Also other companies like medicial firms uses Cold Isostatic Pressing for waists to implement in bodies.

Hot Isostatic Pressing: The Process

During the hot isostatic pressing process the temperature, Argon-gas pressure and holding time will differ depending on the used material. After filling and closing, the HIP vessel is evacuated to purge the air. Then, during heating up,  Argon gas pressure is going in the vessel.  After reaching the needed pressure, the rise in pressure is done through gas thermal expansion. In the holding time, gas-pressure and temperature are on the same level.  After this, a rapid cooling-down takes place, with decreasing pressure and temperature. Chosen temperatures are below approx. 0.8 x T-solidus, to avoid having a liquid phase.

The gas normally used is Argon but in some unique applications other gases or gas mixtures can be used.  The rise in pressure is built up with a compressor and is -depending on the type of compressor – going on quite fast. The gas pressure is isostatic inside and outside the insulation. But the gas density is higher outside the insulation than inside due to the lower temperature; the temperature difference. State of the art Hot Isostatic Press-systems can feature uniform rapid cooling (URC) which circulates lower temperature gas to cool the part at a calculated rate around 95°C/min. This technique cuts cycle time strongly by shortening the cooling stage by as much as 70%. It also makes it possible to combine heat treatment with HIP in one step. The uniform rapid cooling restricts grain growth (similar to the High-Pressure-Freezing technique) and thermal harm of the pieces and avoids surface contamination by using high purity Argon gas. A Hot Isostatic Press-cycle usually lasts from 7 hours up to 24 hours.

Hot Isostatic Pressing

HIP has established itself in the last decade as a leading manufacturing process for the production of special components made from a wide range of metals and ceramics. Hot Isostatic Pressing is a process to densify powders in a HIP furnace at high pressure (1’000 – 2’000 bar) and temperatures from 900 to 1’250°C.  The gas pressure (normally Argon) flows uniformly in all directions to provide isostatic properties.

advantages-hip   Source: EPMA With Hot Isostatic Pressing you

have freedom of sizes, it means it doesn’t matter if you have parts going up from 500g to several tons. Moreover you can reach better properties because of a finer microstructure, it is quite cheap for smaller series and more. Hot Isostatic Presses are available in different types and from different manufacturers. The Hot Isostatic Press HIP from ABRA Fluid is one of the leading Presses around the world. ABRA Fluid is in the market for over 25 years.