Inconel 718: A Superalloy with Lasting Relevance

Metal 3D printing has finally catapulted Inconel, the classic nickel-based heat-resistant alloy, into the 21st century. Inconel 718, the hardened version of Inconel 625, is the latest addition to our growing range of metals for Direct Metal Laser Sintering (DMLS). It is perfect for extreme environments and high temperatures where aluminum and steel would have a creep problem. This makes it ideal for the heavy and aerospace industries, for example in the production of turbine parts and jet engines.

Actually, the story of Inconel 718 begins with the jet engine. The alloy of nickel and chromium was first produced in the 1940s for the development of the Whittle jet engine, because it was just right for this application: strong, heat- and corrosion-resistant, and at the same time cost-effective and light. Tungsten was too heavy, copper melted at even moderate heat, and aluminum and steel were not strong and corrosion resistant enough. Without superalloys like Inconel, aerospace might not have seen such an extraordinary rise. Indeed, perhaps the jet age would never have happened.

Fast forward to this century: There are materials that have evolved from these first superalloys. Inconel 718 is the world's dominant superalloy, and for good reason. Its strength is based on its ability to build up a thick and stable passivating oxide layer at high temperatures up to +704°C, which protects the material from further attack. Inconel also has good tensile, fatigue, creep and fracture strength, making it a workhorse among superalloys.

Inconel is well suited to the production of jet engines and rocket engine components, but aerospace is not the only sector to benefit from this material. Heavy industry also derives benefits for machinery exposed to extreme environments. Gas turbine and instrumentation parts, power and process components, piping, valves and heat exchangers are just some of the applications for which Inconel 718 is suitable.

Machining Inconel 718 is notoriously difficult due to costly tooling, material loss and susceptibility to metallurgical defects. When using this material for fast 3d prints with DMLS, on the other hand, great results can be achieved, especially for intricate designs. With DMLS, the mechanical properties of Inconel 718 are maintained, and thanks to directional solidification, the values of cast and forged parts made from the alloy can even be surpassed with this process.

This means that Inconel 718, with its impressive history, continues to be on the road to success. We can look forward to seeing how the "workhorse" among the superalloys will shape the technology of the future.

Direct metal laser sintering

Direct Metal Laser Sintering (DMLS) at Richconn is an industrial 3D printing process for the Rapid Manufacturing of fully functional metal prototypes and production parts with a run time of 7 days or less. It uses materials that are generally recognized as casting or forging materials, equivalent or superior. DMLS is ideal when geometry or structure of a part cannot be achieved by other processes ( use honeycomb or lattice structures to save weight), and for medical implants.

Inconel 718 is just one of the DMLS materials available from Richconn. Complete list of DMLS materials:

# Aluminum
 # Inconel 718
 # Hot work tool steel
 # Stainless steel
 # Titanium