Hot Isostatic Presses

HIP uses a furnace inside a pressure vessel. Very high pressure gas, usually argon at elevated temperature, is used to consolidate material and remove internal defects such as porosity and microcracks. As HIP uses temperatures very close to those used for heat treatment, creep and diffusion occur, along with mechanical deformation of defects due to extreme external pressure.

As HIP removes internal defects in the load, material properties such as fatigue life, elongation and impact toughness are improved. Subsequent grinding of polishing of surfaces demonstrates excellent roughness values and no unwanted porosity is uncovered by these operations. The HIP has already fixed those.

Modern HIP equipment from Quintus operates up to 2000⁰C (3632⁰F) and 200MPa (30,000 psi). The parameters chosen are material specific, and often an increased pressure can allow lower temperatures to be use, preserving the material microstructure. Of course the HIP cycle used should not exceed the melting temperature of the material to be treated.

HIP is used to consolidate powders, solids and combinations thereof. Materials range from ceramics to metals and composite materials. Light-weight materials, high speed steels, tool steels and super alloys all use HIP, and new generations of materials such as high entropy alloys are also developed using this process.

As the high pressure atmosphere acts in an isotropic manner on the surfaces of components in the hot zone, the mechanical force exerted is even. This means that solid parts do not change shape in the HIP. The gas presses on internal channels in the same way as long as they are open to the gas. Casting, MIM and AM parts are all possible to HIP, and canned powders can be formed into solid components (PM HIP or PM NNS, Powder Metallurgy Near Net Shape).