Upcycling a Tool Steel Residue for Additive Manufacturing Application

This study explores the viability of upcycling the metal residues from machining industry into powders for additive manufacturing (AM). It investigates the production of powders from AISI P20+Ni steel chips using two different techniques: vibratory disc milling (VDM) and planetary ball milling (PBM). These powders were then sieved to select specific size ranges for directed energy deposition (DED) and laser powder bed fusion (L-PBF) processes. The study further aimed to optimize milling parameters to improve process efficiency and powder characteristics. The powders produced by VDM had a flaky morphology, while those produced using PBM had a rounded shape. Microstructural and microhardness analyses were conducted to evaluate particle consolidation and work-hardening effects. Despite the non-spherical shape of VDM powders, they were successfully used in the DED process. The deposit bead evaluation and dilution analysis were conducted, and subsequently correlated with the energy density. A multi-layered volume was printed for further microstructural, chemical, and hardness analyses. In conclusion, the study found that upcycled AISI P20+Ni feedstock can be used in DED, but strict atmospheric control during milling and printing is necessary. Further optimization of process is recommended to ensure chemical composition stability in the printed alloy.