In situ foaming-reaction fabrication of gas-permeable 18Ni300 maraging mold steel using laser powder bed fusion

Purpose Additive manufacturing (AM) technology offers significant advantages for fabricating complex structures and enabling multi-material production. This study aims to fully utilize these two advantages to fabricate gas-permeable mold steel. Design/methodology/approach Gas-permeable mold steel was fabricated by incorporating CrNx foaming agents into the 18Ni300 alloy using Laser Powder Bed Fusion (LPBF) technology. Findings By adjusting the volumetric laser energy from 31 to 57 J/mm³, the fabricated CrNx-doped specimens achieved relative densities of 77%–88%, microhardness values of 138–201 HV, fracture strengths of 333–510 MPa and elongations of 2.2–9.0%. Specimens fabricated using 31 J/mm³ with 5 Wt.% CrNx developed interconnected micro-scale pores throughout the bulk and exhibited a permeability coefficient higher than that of commercial PM-35 gas-permeable steel. Originality/value These results demonstrate that LPBF technology successfully overcomes gas permeability limitations in the conventional mold component fabrication processes.