Research on 18Ni300 alloy powders prepared by close-coupled gas atomization technology used for selective laser melting

The 18Ni300 alloy powders used for selective laser melting were prepared by close-coupled gas atomization, the effects of gas pressure on the particle size (median particle diameter, D₅₀), particle size distribution, particle shape, oxygen content by mass, flowability, and apparent density of 18Ni300 alloy powders were investigated in this paper. The results show that, the gas pressure has the significant effect on these characteristics. With the increase of gas pressure from 3.5 MPa to 4.5 MPa, the particle size decreases, the surface morphology improves, the flowability gets better, and the apparent density increases. When the gas pressure is 4.5 MPa, the 18Ni300 alloy powders show the optimal comprehensive characteristics, the particle size (D₅₀) is 34 μm, the sphericity is 0.77, the oxygen content by mass is 0.02%, the flowability is 17.4s·(50 g)^-1, the apparent density is 4.32 g·cm^-3, and the powder yield in the size of 15~53 μm is 38.1%, meeting the requirements of selective laser melting for the metal powders.