Study on properties of 25Cr35NiNb pre-alloyed powder prepared by atomization
LI Jizhan1，2，FAN Zhichao1，2，XIANG Shulin1，2
（1. Hefei General Machinery Research Institute Co., LTD, National Technology Research Centre on Pressure Ves‐
sel and Pipeline Safety Engineering, Hefei 230031, China; 2. Special Equipment Inspection Station of Hefei Gen‐
eral Machinery Research Institute Co., LTD, Hefei 230031, China）
Abstract：25Cr35NiNb pre-alloyed powder with the particle size ranging from 53 μm to 150 μm was prepared
by vaccum gas atomization (VGA) and plasma rotating electrode process (PREP), respectively. Properties of two
kinds of powder were systematically analyzed using optical microscope, scanning electron microscopy, X-ray dif‐
fraction, laser particle size analyzer, Hall current meter, loose densitometer, inductively coupled plasma spectrom‐
eter, oxygen-nitrogen-hydrogen analyzer and carbon-sulfur determinator. Meanwhile, physical properties of depos‐
its fabricated by laser direct energy deposition with VGA and PREP powders were also investigated in detail. The
results show that microstructures of VGA and PREP powders are basically single-phase austenite columnar crys‐
tals due to the rapid cooling of non-equilibrium solidification. The porosity of VGA powder (9.38%) is much
more than that of PREP powder (2.94%). The sphericity of VGA powder is obviously inferior to that of PREP
powder. In terms of VGA powder compared with PREP powder, the flowability is worse (the Hall velocity of
VGA and PREP powders are 16.04 s/50g and 13.80 s/50g), the apparent or tap density is also lower (the apparent
density of VGA and PREP powders is 4.41 g/cm3 and 4.64 g/cm3, the tap density of VGA and PREP powders is 5.06 g/cm3 and 5.31 g/cm3), the particle size distribution is wider and the content of oxygen and nitrogen are high‐
er. Therefore, density and stress-rupture properties of the deposit fabricated by laser direct energy deposition with
PREP powder are clearly superior to that with VGA powder.
2023, Vol. 33 
