Stainless steel powder produced by a novel arc spray process

Abstract

To accelerate the industrialization of metal additive manufacturing (AM), especially for powder-bed-based processes, there is a huge demand to develop alternative powder manufacturing methods for producing highquality metal powder. In this work, 17-4PH stainless steel powder was produced using a novel gas atomization method based on arc spraying process. The morphology of the produced powder, as well as the mechanical properties of printed specimens using SLM, were characterized and tested. The obtained results were compared with a commercial 17-4PH steel powder and its SLM specimens. The particle size analysis demonstrated that this novel atomization method has the advantage of producing powder in small quantities with a high yield of fine particles by using commercially available wire. Arc-sprayed powder exhibited higher sphericity, smoother surface and absence of satellite particles compared to commercial powder. After SLM processing with optimal process parameters, specimen with a porosity less than 0.1% can be obtained using arc-sprayed powder, which was significantly lower than that of using commercial powder - exhibited a porosity of 2%. Specimens built with arc-sprayed nitrogen-atomized powder contained martensite phase with a small amount of retained austenite while the specimens built with commercial argon-atomized powder contained only martensitic structure. The presence of retained austenite phase enhanced the mechanical behavior of the printed specimens. Metallic powder, produced by arc spraying gas atomization method, is well suited and even preferred for additive manufacturing.

Keywords

• Powder production
• Selective laser melting
• Arc spray
• 17-4PH