Preparation, Characterization And Application Of Spherical Metal Powder For Addictive Manufacturing

Spherical metal powders with low oxygen content, narrow particle size distribution, high sphericity, unlike traditional metal powders used in powder metallurgy, are mainly used in 3D printing and injection molding and other advanced forming methods.which have a very high market application prospect and economic benefit.This article states gas atomization preparation methods and related influence factors in detail. On the basis of the inert gas atomization equipment developed by using supersonic pulse, the the composition, microstructure, surface morphology, particle size and particle size distribution of prepared spherical 2A14 aluminium alloy powders, copper powders and 304 stainless steel powders were studied by XRD, optical microscope, scanning electron microscopy (SEM), laser granularity analyzer; The influence of pressure, nozzle type and the property of metal to spherical metal powders particle size, particle size distribution and the influence of surface topography were studied; The preparation of spherical 603 stainless steel powders were formed by 3D printing, and 3D printing stainless steel phase, microstructure, nano hardness and elastic modulus etc were analyzed. In this paper, the study found that:(1) Under this experimental condition, the metal powders prepared by the supersonic pulse inert gas atomization equipment, with no impurity phase, smaller mean particle size and narrow particle size distribution, the approximate normal distribution, have high sphericity, and only a few powders are with satellite ball.(2) With the increase of gas atomization pressure from 5.5 MPa to 6.0 MPa, average 2A14 aluminium alloy powders particle size decrease, the powders prepared at 6.0 MPa having the minimize size; Atomization pressure increased from 5.5 MPa to 6.0 MPa, sphericity of aluminum powders is improved and when atomization pressure is more than 6.0 MPa, with the increase of atomization pressure, satellite ball phenomenon is more and more serious. Annular nozzle with gap compared with nozzle with holes, the particle size of metallic powders prepared by annular nozzle with gap is more small, and its spherical degree is higher, but its satellite ball phenomenon is a bit serious than metal powders prepared by annular nozzle with holes. Under the same conditions, the greater the surface tension and viscosity of molten metal is, the more spherical metal powders production is and the greater the particle size of powders is; Molten Metal with smaller surface tension and viscosity is easier to get metal powders with relatively poor spherical degree, but the smaller particle size.(3) The element percentage of 3D printing 630 stainless steel is 0.7% Si,15.89% Cr, 0.91%Mn,0.47%Ni,3.99%Cu, and 73.83%Fe. The main phases are martensite and austenite phase. Its microstructure is composed of columnar crystal and dendritic crystal. The dendritic crystal tissue section for cellular organization is uniform, close under the scanning electron microscopy.Nano indentation hardness of the 3D printing is 5679.0 MPa on average, and the average elastic modulus is about 250.4 GPa.