Some like it hot: How Linde supports Hot Isostatic Pressing

Hot Isostatic Pressing – when high pressure and temperatures up to 2,000 degrees Celsius join forces to eliminate porosity of working parts. Linde has a gas management concept ready and waiting for clients who want to build or optimise their HIP facilities.

With additive manufacturing becoming increasingly important for the industry, so is the post-processing step known as Hot Isostatic Pressing (HIP). But compared to 3D printing, HIP has been around much longer. “It’s a form of heat treatment that has existed for 50 or 60 years,” says Matthias Bors, Senior Expert Heat Treatment at Linde.

When metal work pieces are cast, sintered or – a more recent phenomenon – 3D printed, this often results in a certain porosity of the produced components. They lack the density needed for highly stressed applications like aerospace structural parts, medical implants or automotive engine parts. The solution: HIP. “The work-pieces are treated in a vessel under high isostatic pressure and temperatures up to 2,000 degrees Celsius, depending on the material,” explains Bors. The pressure is applied with an inert gas like argon or nitrogen. Under these conditions of heat and pressure, the material is densified and pores or defects disappear. This improves the mechanical properties and fatigue performance of manufactured parts.

Re-use of argon: a huge cost-saver for clients

High-purity argon, one of Linde’s fields of expertise, is typically used to provide the necessary inert atmosphere. But Linde’s contribution doesn’t stop at providing the gas. The company also supports HIP plant operators with customised gas management systems and custom-tailored solutions for re-use of valuable argon. Besides decades of experience in gas supply systems, Linde draws on company-owned innovations in the field of gas management systems in Hot Isostatic Pressing. Already in 2004, Linde designed the so-called multi-section buffer technology to reuse argon. Those systems can save up to 70% of the gas used.

Today, Linde has a concept ready and waiting for clients who want to build or optimise their HIP facilities. Depending on the size of the plant, Linde is able to adjust the size of components like tanks, pumps, gas and reuse buffers to a client’s demand. “Gas supply systems today are often over dimensioned, which costs operators a lot of money,” says Bors. “Our goal is to tailor the size of the systems to the needs of the client.” This in turn also has the potential to minimise capital expenditures and operational costs like maintenance, service or energy demand.

Anticipatory planning: part of Linde’s consultation approach

Paolo Kirchpfening emphasises that Linde’s consultation approach goes beyond selling products. “At an early stage of a project the objective is not to sell the maximum of supply hardware, but to design the layout based on the present requirements.” Not every HIP facility, he stresses, needs a gas reuse system – those installations only pay off at a certain level of argon consumption. “Sometimes it makes more sense to scale-up the supply equipment at a later stage. This is a possibility we anticipate in our early planning.”

With the demand for Hot Isostatic Pressing on the rise, Linde is constantly looking to improve the technology – for instance by transferring knowledge from other fields of expertise. “We are currently working to apply our pumping technology that we have perfected for hydrogen to the HIP process,” says Bors.

Picture shows the Quintus model QIJ 122 for HIP processes
HIP vessels such as the Quintus QIH 122 apply a temperature of 1,400 degrees Celsius and a pressure of 30,000psi of Argon. © Quintus Technologies