Preparation and Characterization of Fine 316L Stainless Steel Powders Prepared by Gas Atomization
Atomization technique has the powder production advantages of high production efficiency, low cost and good sphericity. In this paper, 316L stainless steel powders were prepared in nitrogen atmosphere by using self-designed nozzles. The fine powders yield, particle size distribution, particle shape and microstructure of powders prepared by different nozzles and different pressure were studied. Particle analyzer was used to characterize the powders. Results show that the powders produced by more complex nozzle structures and higher pressure have higher yield and better effect sphericity. The slender powders are fewer. The average elongation is below 0.4, and the average O.Bluntness values are above 0.6. With the decrease of pressure, the average of O.Bluntness value increases and the sphericity of powders is improved. The average outgrowth values are below 0.2, and the satellite powders are lesser when the pressure is greater. The flowability of the 316L stainless steel powders prepared by lower pressure were better, while the powders prepared by the higher pressure have extremely poor fluidity. The fluidity was significantly improved after sieving the fine powders less than 25 µm. The surface and the internal microstructure of 316L stainless steel powders prepared by different processes are mainly cellular and dendrite structures.
KeywordsAtomization Particle shape 316L stainless steel
The authors gratefully acknowledge the financial supports from Guangdong science and technology research project (No. 2014B010129003; 2016B090931006; 201604016049; 2017B090901025).
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