Structure and properties of corrosion-resistant steel obtained by selective laser melting

The objects of study were stainless steel powder 12Kh18N10T of the 20–63 μm fraction and experimental samples obtained on the basis of it by selective laser melting (SLM). The powder was obtained by spraying with argon at a temperature of 1640 °C and a pressure of 27 bar. The particles have the dendritic-cellular structure, with a decrease in their size (<35 μm), the cellular structure prevails, and the dendritic one almost disappears. The distinctive particle size is d50 = 37 μm, d100 = 67 μm. The differential distribution curve is close to the Gaussian form, and asymmetry is associated with satellite and the presence of a small number of particles less than 20 microns in size. The fluidity of the powder was 3,27 g/s, and the bulk density was 4,41 g/cm3. The density of the 12Kh18N10T steel samples grown at the Concept Laser M2 facility with a laser power of 180 W and a speed of 700 mm/s averaged 7,89 g/cm3. Since the density of compact steel is 7,95 g/cm3, the obtained material has enough high density. The microstructure of the 12Kh18N10T sample was described by continuity, the absence of pores and cracks. It was a solid solution of austenite. The average size of coherent scattering regions in the grain volume was 19 nm. The observed arcuate boundaries of parallel semicircular tracks are due to heat removal during crystallization through SLM. The elongated crystallites in the tracks are oriented inward from this boundary. The microhardness of the samples in the transverse plane of the thin section is higher than the microhardness of the planar plane. But the microhardness of the samples obtained from the powder by the SLM is higher than that of the standard compact alloy. Tensile strength and elongation are 651 MPa and 47 %, respectively. The increase in strength is probably due to the grinding of structural parameters in SLM. The fracture surface of the samples is characterized by a pronounced viscous type.

atomized powders, selective laser melting, austenitic steel, structure, mechanical properties

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