Carbon Particle In-Situ Alloying of the Case-Hardening Steel 16MnCr5 in Laser Powder Bed Fusion

• Main Authors: Matthias Schmitt, Albin Gottwalt, Jakob Winkler, Thomas Tobie, Georg Schlick, Karsten Stahl, Ulrich Tetzlaff, Johannes Schilp, Gunther Reinhart
• Format: Article
• Language: English
• Published: MDPI AG 2021-05-01
• Series: Metals
• Subjects: additive manufacturing; PBF-LB/M; in situ alloying; case-hardening steel; 16MnCr5; gears
• Online Access: https://www.mdpi.com/2075-4701/11/6/896

The carbon content of steel affects many of its essential properties, e.g., hardness and mechanical strength. In the powder bed fusion process of metals using a laser beam (PBF-LB/M), usually, pre-alloyed metal powder is solidified layer-by-layer using a laser beam to create parts. A reduction of the carbon content in steels is observed during this process. This study examines adding carbon particles to the metal powder and in situ alloying in the PBF-LB/M process as a countermeasure. Suitable carbon particles are selected and their effect on the particle size distribution and homogeneity of the mixtures is analysed. The workability in PBF-LB is then shown. This is followed by an evaluation of the resulting mechanical properties (hardness and mechanical strength) and microstructure in the as-built state and the state after heat treatment. Furthermore, potential use cases like multi-material or functionally graded parts are discussed.