Microstructure of 18Ni300 maraging steel powder prepared by vacuum-inducedmelt
gas atomization
KONG Shuilong1，2，SHI Lei1，3，LI Feng1，2，JIN Ying1，3，WENG Ziqing1，3，SHI Jinguang1，3
1Zhejiang Metallurgical Research Institute Co. Ltd，Hangzhou 310011，China；2 Zhejiang Province
Mmetallurgic Products Quality Test Station Co.，Ltd，Hangzhou 310007，China；3 Zhejiang Asia General
Soldering & Brazing Material Co.，Ltd，Hangzhou 310030，China）
Abstract：18Ni300 maraging steel powder was prepared by vacuum- induced- melt gas atomization(VIGA). The
size distribution, morphology and microstructure of the powder was investigated by laser particle size analyzer,
scanning electron microscopy (SEM) and X- ray diffraction(XRD). The results show that the partical size of
18Ni300 maraging steel powder is normal distributed , the medium diameter is 74.22 μm, and the mass fraction of
the powders partical size less than 45 μm is up to 28.6% . The powder is spherical or near-spherical. With the increasing
of partical size, the worse micro-morphology with satellite-grains around the surface and the gas-hole in
the powders appear. The inner micro-structure of the powders less than 45 μm is swelling crystal. Dendrites appear,
the width of primary crystal axis and secondary dendrite arm spacing increase with the partical size growing, even
the radial secondary dendrites appear. The phase of the powder is bcc-structure martensite , with no obvious peak
of Ni3X strengthen phase.
2021, Vol. 31 
