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Gas atomization, plasma atomization, rotary atomization, water atomization,
and plasma rotating electrode process are the techniques used for production of
metal powder for powder-bed fusion AM systems.

Among those techniques, gas atomization and plasma atomization are widely used because
of its powder shape, particle size distribution, and adjustment of chemical compositions.
Recently, however, the feasibility of utilizing water atomized powder is a subject for discussion.

The problem about that is it introduces higher level of oxygen and irregular powder shape.
When the powder’s sphericity is low, the powder would not be spread in a consistent and even manner.
Because of that, porosity can be introduced into the part and surface roughness will increases.

Increased level of oxygen has the ability to react with surface-active elements in melt pool,
and its flowability becomes unstable.

By optimizing the parameters of the machine, it is reported that it’s possible to make parts with water atomized
316L powder which exceeds the minimum density of 99.5% of the theoretical density. (Fig.1)(Hoeges S et al., 2017)[1]

In this report, it says that there were no significant difference in tensile strength but by forming SiO2, MnO, and
Cr2O3, reduce in impact strength and fatigue strength is concerned.

 

Fig.1 水アトマイズ粉末で作った316L造形品の断面観察画像[1]
Fig.1 Sectional image of builded piece using water atomized 316L [1]

 

As you can see, depending on the reactiveness of the material and the usage of the parts,
you can reduce the production cost by using water atomized powder.

 

References
[1] Hoeges S, Zwiren A, Schade C, Metal Powder Report 2017; vol.72 (2): 111-117


Email : info.sp@solize-group.com / TEL : +81-45-937-0390
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