Hot Isostatic Pressing (HIP) established itself in the past decade as a competitive and proven process of densifying complex and highly specified components made from a wide range of metals. These components are currently being used in a number of industry sectors that have highly demanding environments, e.g. aerospace, offshore, energy and medical.
HIP is a process to densify powder, cast or sintered parts in a furnace at high pressure (100-200 MPa) and at temperature from 900 to 1250 °C. The gas pressure acts uniformly in all directions to provide isotropic properties and 100% densification. This technology is complementary to other powder metallurgy processes, such as MIM technology, pressing, sintering or the new additive manufacturing technology (3D printing). Event, it is used in combination with these PM processes for part densification.
It has developed over the years to become a high-performance, high-quality and cost-effective process for densification of metal components.
Process of HIP
The HIP technology is characterized by huge pressure, which is applied while the temperature ensures diffusion on the contact surface between powder particles, until all pores are closed and 100% density is achieved.
Closure of residual internal porosities by HIP through combination of pressure and temperature. (Source: EPMA)
HIP technology is used as densifying process for cast and sintered parts and MIM parts, as well as during diffusion joining of metal components.
Schematic of HIP furnace (Source: Introduction to PM HIP technology, EPMA)
HIP technology offers many benefits in the following key areas.
Component quality and performance:
- fine and isotropic microstructures produces by HIP,
- reduction of number of welds on complex parts,
- dense without segregation.
- near-net shapes, net shapes or bimetal constructions,
- use of composite materials.
- lean manufacturing route, leading to shorter production lead-times,
- reduction of machining need,
- production of single parts where previously several were required,
- in case of near-net-shape and net-shape parts due to the excellent material yield compared with conventional metallurgy.
Reduced environmental impact.
According to previously mentioned information and facts, the HIP technology is proved as a high quality and cost effective technology.