Compared to traditional manufacturing methods, PM HIP technology offers significant benefits in applications that require improved material characteristics (strength, corrosion prevention) and a high internal integrity of the material. The technology was initially developed for the most demanding military applications and aviation, and today it is widely used in several industries, e.g. with oil and gas applications.
The production process from fusion to finished product is divided into three phases. The powder is produced using inert gas atomisation. It is packaged in metal capsules that shape the product into the desired form. The capsules achieve their full density in a high pressure and temperature during hot isostatic pressing (HIP).
The fusing conducted in an induction furnace includes the induction heated ladle that can be used to add other compound materials to the liquid in a protected atmosphere. The ladle also enables mixing and temperature control throughout the fusing process.
When the molten material is removed from the ladle, it is directly transported to the atomisation chamber. The molten steel is atomised using sprays of inert gas, and the atomised liquid solidifies into small, round particles that are very clean and whose oxygen content is very low. Their diameter is typically less than 500 microns. The powder is stored in inert gas in hermetically sealed containers.
The powder is packaged into steel capsules that are produced by forming and welding sheets. The capsules have been designed to give the finished product the desired form. Composite products can be produced by designing the capsules so that they have different compartments for different materials, or by incorporating parts made out of solid material into the structure.
The capsules are placed into the HIP unit (Hot Isostatic Pressing), where they are subjected to high pressure and temperature. The HIP parameters for the pressure, temperature and time are determined so that the material reaches its full density and the required characteristics.
Depending on the material and the application, the products may be heat-treated, worked and exposed to different quality assurance operations, such as ultrasound scans, dye penetrant checks, inspections of mechanical characteristics, etc. The carbon steel material used in encapsulation will still be present in the product after the HIP treatment. It is removed with machinery or a corrosive acid treatment.