Parameter Optimization for Laser Powder Bed Fusion of the Cases-Hardening Steel 20MnCr5

Additive manufacturing, especially powder bed fusion of metals using a laser beam (PBF-LB/M), allows the build-up of complex parts. Therefore, PBF-LB/M is already used in multiple fields, such as medical or aerospace industry. To promote the widespread use of AM within the automotive sector materials such as case-hardening steels have to be available due to their use in drivetrain parts e.g. gears and shift forks. In this contribution, the processing capability of the case-hardening steel 20MnCr5 via PBF-LB is examined. At first, the powder properties of the material are examined regarding particle size distribution, porosity and flowability. As a second step single tracks are used to determine a preliminary parameter window. Subsequently, density specimens are manufactured with varied processing parameters. Analyses show that relative densities above 99.5 % are achievable. Subsequently, the microstructure is examined and mechanical properties determined showing a correlation of hardness and applied energy density.