Characterizations of the anisotropic features of the phase, texture and deformation behavior of laser powder bed fusion-processed H13 steel

H13 steel with a relative density of approximately 99.9 % was fabricated by LPBF with 200 °C preheating (H13−200). Samples were built along horizontal (0°, H13 200H) and vertical (90°, H13–200 V) orientations relative to the build platform to investigate the anisotropy of microstructural features and mechanical properties. Despite similar grain morphology, size, and crystallographic texture, the retained austenite (RA) content varied between orientations. H13–200 V exhibited higher RA fractions due to enhanced intrinsic tempering. Compared to previously reported H13 steel processed with similar or no preheating, H13–200 demonstrated higher tensile strength and elongation, with no notable tensile anisotropy observed. The deformation and damage evolution mechanisms were analyzed. Strain hardening and ductility were promoted by the formation of a fine cellular substructure and the transformation-induced plasticity effect from RA. Fractographic and microstructural analyses revealed that RA suppressed crack propagation and contributed to damage tolerance. These results demonstrate that moderate preheating can effectively tailor the phase composition and enhance mechanical performance without introducing notable anisotropy in LPBF H13 steel. • Achieved isotropic tensile properties in LPBF-processed H13 steel. • Retained austenite and cellular substructure enhanced strain hardening behavior. • Martensitic transformation (N W) altered the orientation of prior columnar austenite. • Variations in tensile properties were caused by differences in retained austenite content.