Finland’s largest 3D-printed pressure vessel successfully tested

ANDRITZ Savonlinna Works Oy and the FAME Ecosystem have reached a significant milestone in the field of 3D printing: Finland’s largest metal 3D printing vessel has been successfully tested. The tests according to the EN 13445-3 pressure vessel standard were conducted by LUT University and delivered impressive results.

The pressure vessel was produced using ANDRITZ Savonlinna Works Oy’s Direct Energy Deposition (DED-Arc) technology, which uses an electric arc as the energy source. This method is also known as Wire Arc Additive Manufacturing (WAAM). The container, made of acid-resistant stainless steel (316L), weighs around 300 kilograms, has a diameter of 900 mm and a height of 1600 mm. Elomatic was also involved in the design phase.

The comprehensive tests carried out by LUT University included both non-destructive and destructive tests. The aim was to increase the pressure until the container failed. This happened at an impressive pressure of 111 bar.

“The test results have been published in an article for the benefit of the entire AM community. We are proud to have made such a significant effort publicly available,” says Eetu Holstein, FAME Ecosystem Lead at DIMECC Oy.

The tests also included non-destructive methods such as penetrant testing, as well as material and geometry performance tests. The final parts were compared with the CAD model and showed a high degree of conformity, which is due to the precision of the printed weld seams.

“This vessel was designed for an operating pressure of 10 bar, which includes the safety factors. The preliminary calculation showed that the rupture would occur at around 90 bar, i.e. the actual durability far exceeded expectations. It must be noted that in real production pieces, the test pressure of the pressure vessel is usually only done at around 1.5 times the operating pressure, i.e. in this case the test pressure would have been only 15 bars,” says Santeri Varis, Additive Manufacturing Manager at ANDRITZ Savonlinna Works Oy.

During the pressure test, water was pumped into the container and the changes in diameter were monitored. Up to a pressure of 66 bar there were no changes, only at 80 bar did the shape show slight changes. At a pressure of 111 bar, water leaked out and a small crack formed near the legs of the container.

“Under 66 bars, there were still no noticeable changes in the vessel. The shape started to give way after 80 bars. We continued the test so long that some water leaked out of the vessel at 111 bars. At that point, a small crack appeared next to the legs of the vessel. The diameter had expanded by seven percent. The result is very good for a piece like this, which is designed to withstand much lower pressure,” says Doctoral Researcher Kalle Lipiäinen from LUT University.

The article “Manufacturing and mechanical performance of a large-scale stainless steel pvessel fabricated by wire-arc direct energy deposition” was published in Materials & Design, Volume 243, July 2024.