Belgorod State University, Belgorod, Russia

I. S. Nikitin, Cand. Eng., Researcher, Lab. of Mechanical Properties of Nanostructured Materials and Superalloys, e-mail: nikitin_i_s@mail.ru
A. O. Semenyuk, Junior Researcher, Lab. of Bulk Nanostructured Materials, e-mail: semenyuk@bsuedu.ru
R. S. Chernichenko, Junior Researcher, Lab. of Bulk Nanostructured Materials, e-mail: chernichenko@bsuedu.ru
E. A. Voropaeva, Cand. Eng., Researcher, Lab. of Bulk Nanostructured Materials, e-mail: povolyaeva@bsuedu.ru
N. R. Dudova, Cand. Phys.-Math., Leading Researcher, Lab. of Mechanical Properties of Nanostructured Materials and Superalloys, e-mail: dudova@bsuedu.ru
S. Yu. Mironov, Dt. Phys.-Math., Leading Researcher, Lab. of Mechanical Properties of Nanostructured Materials and Superalloys, e-mail: mironov@bsuedu.ru

The effect of selective laser melting modes on the roughness and density of 17-4 PH high-chromium steel products was studied. Increasing the volumetric energy density from 50 to 220 J/mm³ during printing of workpiece resulted in a decrease in Ra from ~15 to ~6 μm on the top surface and an increase in Ra from ~12 to ~22 μm on the side surface. It is shown that the greatest contribution to the formation of roughness on the top surface of the workpieces is made by laser power, which is approximately 30 times greater than the contribution from the scanning speed. For the side surface, the influence of laser power on roughness formation is less pronounced and only ~2.5 times exceeds the contribution of the scanning speed. A range of modes providing a minimum level of roughness on the top surface of the workpiece is identified: laser power from 170 to 300 W and a scanning speed from 500 to 1000 mm/s. For the side surface, minimal roughness is ensured by printing with a laser power of 150 to 300 W and a scanning speed of ≥700 mm/s. Reduced roughness of both surfaces is achieved in a narrow range of laser power from 150 to 300 W and a scanning speed of 1000 mm/s. It was established that the density of workpieces does not depend solely on the volumetric energy density, as a complex characteristic of the printing mode, but is determined by a combination of energy density and laser power/scanning speed. The mechanisms of roughness formation on the top and side surfaces of the workpiece and the relationship between roughness and porosity are examined.
This study was supported by grant No. 25-79-10342 from the Russian Science Foundation (https://rscf.ru/project/25-79-10342/) using equipment from the Belgorod State University Joint Research Center “Technologies and Materials.”
The authors would like to thank A. A. Kalinenko for assistance in obtaining the experimental data.

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