Investigation of the build orientation effect on magnetic properties and Barkhausen Noise of additively manufactured maraging steel 300

Abstract

Additive manufacturing allows the production of complex geometries with freedom for layers construction. Build orientation causes mechanical anisotropy and may affect the crystallographic structure enabling custom-tailored properties for the product. Despite the production advantages provided by the Powder Bed Fusion (PBF) process, some inherent defects, such as porosity and residual stress need monitoring to guarantee the agreement with the material application’s requirements. Thus, this study examined the magnetic properties and the residual stress of maraging steel 300 specimens built by PBF in three build orientations (XYZ, XYZ-45, and YZX). The Rowland Ring method enabled the assessment of the static magnetization curve and the quasi-static hysteresis loop. The Barkhausen Noise (BN) characterization followed the Design of Experiments (DOE) to investigate anisotropic effects in two perpendicular directions along the surface (φ = 0° and φ = 90°). Magnetic permeability, coercivity, remanence, and power loss changed according to the build orientations used in the PBF process, and possible reasons for these changes associated with the PBF process are discussed. Moreover, residual stresses evaluated by X-ray diffraction for the three build orientations correlated to BNrms with r = 0.99 when φ = 90°. The XYZ specimen revealed a compressive stress, which also decreased the BN intensity, though XYZ-45 and YZX presented tensile residual stresses. Thus, the Barkhausen Noise could be used to inspect the residual stress of parts produced by PBF with different build orientations, improving quality management.