EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Currently, most of mechanical components made by powder metallurgy (PM) use steel powders that also contain nickel carbonyl. Nickel-containing steel powder allows to obtain parts with excellent density, toughness and fatigue strength, but at the same time Nickel is a carcinogenic element with high costs. For this reason, in the last years, metal powder manufacturers have developed new, sustainable and "green" powders that do not contain Ni. One of the limits to the diffusion of these powders is the lack of both exhaustive data regarding the mechanical properties of the Nickel-free steel powders (NFP) and examples of successful applications in the production of high-performance PM components. NEWMAN project (Nickel frEe poWders for high performance compoNents), supported by EIT Raw Materials, aims to promote the spread of the use of NFP. The scope of this project is the validation of use of NFP for the production of high- performance mechanical components for the automotive sector and optical measuring systems. During the project, a characterization of three different powders: Astaloy 85Mo + 0.25C, Astaloy CrA + 0.25C and Astaloy CrA + 0.6C was performed. The characterization included: density, microstructural analyses and a complete mechanical characterization by means of tensile, fatigue, impact and tribological tests. The obtained results prove that nickel-free powders, when combined with an appropriate process optimization, heat treatment and design, can replace traditional nickel powders or steels in the production of sliding sleeves for automotive gearboxes and precision components used in measuring machines.