HIP has come in to its own since it reached a comparable scale to castings and forgings, and has become recognised as an economic competitor to forging and casting in applications with higher raw material costs.
HIP is a material treatment process that involves the use of heat and pressure to improve the physical properties of a material. It’s typically performed on metals and ceramics. When either of these types of materials are exposed to heat and pressure, their physical properties change.
With HIP, the material is placed inside an HIP machine. HIP machines feature both a furnace and pressure vessel that changes the physical properties of the material. Argon gas is forced inside the HIP machine, thereby increasing the vessel’s temperature as well as pressurizing the vessel. After allowing the argon gas to sit for a specific amount of time, the vessel is cooled. When finished, the treated material is removed from the vessel.
HIPs come in many forms, shapes and sizes and can operate at a range of temperatures and pressures.
HIP can be used to press a range of materials from Ceramics and Aluminium castings to Nickel based ‘super-alloys’ for all sorts of applications.
HIP allows the impurities (pores) to be squeezed out of materials in order to improve a number of their material characteristics. For example, in sintering (powder metallurgy) the process compresses a volume of metal powder at such high pressures and temperatures, that through a combination of deformation, creep and diffusion bonding you actually create a product with an homogenous annealed microstructure (compact solid) with minimal or no impurities in the material.
It allows manufacturers to create stronger and more durable products. When certain materials, such as metals and ceramics, are exposed to heat and pressure, they become stronger and more durable.
Some manufacturing companies use HIP to minimize the production of scrap material. By treating the material with pressure and heat beforehand, the material will typically create less scrap when used in other manufacturing processes.
Metal powders can be converted into solid material using HIP. For this type of HIP process, however, more pressure is required. It’s not uncommon for metal powders to be exposed to up to 15,000 pounds per square inch (PSI) of pressure. Combined with heat, the pressure squeezes the metal powders together, resulting in the formation of a solid material.
