Preparation of Spherical Iron Powder by High-Temperature Re-melting and Spheroidizing

Spherical metal powders are in great demand in the novel manufacturing industry, such as 3D printing, plasma spraying, and metal powder injection molding. For the efficient production of spherical metal powder, an innovative method to prepare spherical metal powder was proposed in this paper through re-melting and spheroidizing the irregular shape metal powders at high temperatures. And, the spherical iron powder is successfully prepared using direct reduced iron powder. The morphology, particle size distribution, spheroidization rate, and gas content of the powders prepared were characterized. When the gas ratio of hydrogen increases in the spheroidizing atmosphere, the oxygen content of the treated powder decreases subsequently. Meanwhile, the change in nitrogen and hydrogen content is not obvious. After treatments at 1833 K, the particles below 100 μm present smooth surfaces, and no hollow particles and satellite spheres exist. And, the spheroidization rate is close to 100%, which is greatly beneficial to improve the flowability.