Potential Utilization of Grinding Waste for Metal-Cored Wire Production in Additive Manufacturing

This study investigated the upcycling of grinding waste into metal-cored wire (MCW) for additive manufacturing (AM) via Directed Energy Deposition-Arc/Metal (DED-Arc/M). The waste originated from grinding the material X153CrMoV12 (1.2379, AISI D2), a cold work tool steel commonly used in toolmaking. Based on the chemical characterization of the recycled swarf and the use of the low-temperature transformation (LTT) approach in AM, X36CrMoWVTi10-3-2 tool steel was selected as the target material for upcycling. Following mechanical and thermal separation of the heterogeneous grinding slurry mixture, up to 36 mass% of grinding chips in the 63-125 μm fraction could be added to the powder filling of the MCW. Due to residual abrasive particles, the chip fractions showed higher C and Si content than the original material. Samples were fabricated by DED-Arc/M using both conventional and recycled-content MCWs. The samples produced exhibited almost identical properties. Despite the high density of both materials, exceeding 99.3%, larger individual pores were detected in the recycled material, presumably indicating incomplete separation of the cooling lubricants during the recycling process. Examinations using a scanning electron microscope revealed an identical microstructure. No abrasive particles remaining from the grinding process could be detected after AM. Instead, partially dissolved W- and C-rich particles with a high liquidus temperature from the MCWs were detected in both materials. Finally, the samples were found to have an identical hardness of ∼540 HV10 in the as-built state.