Investigation of Influence of the Parameters of the Process of High-Pressure Water Spraying on the Morphology of Stainle
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INVESTIGATION OF INFLUENCE OF THE PARAMETERS OF THE PROCESS OF HIGH-PRESSURE WATER SPRAYING ON THE MORPHOLOGY OF STAINLESS-STEEL POWDERS O. A. Skachkov,1 S. Yu. Manegin,2 I. A. Gulyaev,3 A. V. Mezhevov,4 and P. O. Zhukov5
UDC 621.762
We study the process of high-pressure water spraying of powders of austenitic stainless steels in a smallscale installation with a furnace capacity of 25 kg. The technological characteristics of the obtained powders are analyzed depending on the conditions of spraying. It is shown that, as the ratio of the amounts of high-pressure water and sprayed metal melt increases, the shapes of formed particles change from rounded and even spherical to irregular and spongy with highly developed surfaces. This effect is explained by an increase in the rate of cooling of formed particles, which prevents the possibility of their spheroidization in the course of motion from the focus of spraying to the level of cooling water in the chamber. Hence, by changing the ratio of the amounts of high-pressure water to the amount of the melt, we can get high-quality powders of prescribed shapes. These powders can be used in various fields of the contemporary industry. Keywords: spraying of stainless steels with water, technological parameters, morphology of powder particles, spherical particles.
At present, in various branches of industry, there is a noticeable need in alloyed powders required for the manufacturing of products obtained both by the classical methods of powder metallurgy (i.e., by pressing and sintering) and by using the newest 3D and powder-injection molding (PIM) technologies [1–4]. Note that the technologies of pressing and sintering are based on the use of powders with grain sizes smaller than 200 μm and the developed surfaces of particles of irregular shapes. At the same time, for the 3D or PIM technologies, it is necessary to have powders with particles of round or (better) ideal (spherical) shape and sizes smaller than 100 μm. Moreover, for the SLS processes, the required particles should be even smaller than 50 μm [5]. The main part of the powders of alloyed steels produced in the world are obtained by the method of highpressure water spraying, and the Hoganas AB Firm (Sweden) proves to be the absolute leader in this field [6]. At present, this technology is extensively applied and proved to be quite efficient due to the simplicity of the process and its relatively prime low cost combined with high productivity. The powders obtained by this method are characterized by high chemical homogeneity and have no internal porosity, which enables one to produce denser and more homogeneous products. “Bardin TsNIIchermet” Institute, Moscow, Russia. 1 E-mail: [email protected]. 2 3 4 5
E-mail: [email protected].
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E-mail: [email protected]. E-mail: [email protected].
Translated from Metallurg, Vol. 64, No. 8, pp. 43–48, August, 2020. Original article submitted May 19, 2020. 780
0026-0894/20/0708-0780
© 2020
Springer Science+Business Media, LLC
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