Development of FeSi steel with increased Si content by Laser Powder Bed Fusion technology for ferromagnetic cores application: microstructure and properties

Additive manufacturing (AM) technology like Laser Powder Bed Fusion (LPBF) represents a valid alternative for the production of ferromagnetic cores. In this study, two grades of steel were considered, with standard (3.0 wt.%) and high (6.5 wt.%) Si content. The study is aimed at optimizing the process parameters in order to obtain components suitable for magnetic applications. Moreover, the effect of post-production annealing heat treatment on the microstructure evolution is investigated. The investigation included microstructural analysis by optical microscope (OM), Dynamic Scanning Calorimetry (DSC) analysis and electro-magnetic measurements (EM) on samples with optimized geometry. Results shows that both types of steel can be produced free from defects. Even if the magnetic behaviour of FeSi6.5 samples by AM do not fully reproduces that obtained on electrical steels manufactured by standard process, it appears quite promising. In this framework the optimization of post- production processes represents a promising challenge to meet market demands.