INFLUENCE OF SELECTIVE LASER MELTING WITH ADDITIONAL REMELTING OF RECRISTALLISED LAYERS ON THE STRUCTURE AND PROPERTIES OF HEAT-RESISTANT STEEL 15X25T

Research into the selective laser melting (SLM) process has led to a significant improvement in the quality of synthesized objects. With incorrect selection of process modes during the production of heat-resistant steel products, various defects (pores, cracks, lack of fusion) may occur, which significantly reduce the mechanical properties of the material. Elimination of defects in selective laser melting can be achieved by optimizing the laser beam processing mode. As such a processing strategy, it is proposed to re-melt the formed roller or heat-treat it with laser radiation without melting the metal during a second laser pass without powder feed. The study of the influence of repeated laser remelting of crystallized tracks on the microstructure and mechanical properties of parts made from powders of corrosion-resistant and heat-resistant steels is currently relevant. This article presents studies of the influence of growth modes of heat-resistant steel 15X25T samples on the structure and mechanical properties. The mechanical properties, heat resistance and corrosion resistance of 15Kh25T steel samples obtained by SLM with additional remelting of previously recrystallized tracks were investigated. It was shown that the obtained material surpasses the deformed semi-finished product made of 15Kh25T steel in a set of mechanical properties. Significant residual stresses at a level of 236 MPa were revealed in 15Kh25T steel samples. The use of additional remelting allows this level to be reduced to 108 MPa. The results of microstructural analysis of the surface layer of 15X25T steel samples obtained by SLM with additional laser remelting of recrystallized tracks (laser power 135 W and scanning speed 450 mm/s) revealed a decrease in the surface roughness of the sample Rz from 62 to 12 – 15 μm.

1. Saprykina N.A., Saprykin A.A. The influence of layer-by-layer laser sintering conditions on the quality of the sintered surface layer of co-balt-chromium-molybdenum powder. In: Cur-rent issues in mechanical engineering: Pro-ceedings of the First International Scientific and Practical Conference. Novosibirsk: Izd-vo NGTU. 2014:119–123. (In Russ.).

2. Zhou X., Li K., Zhang D., Liu X., Ma J., Liu W., Shen Z., Textures formed in a CoCrMo alloy by selective laser melting. Journal of Alloys and Compounds 2015; 631:153–164. https://doi.org/10.1016/j.jallcom.2015.01.096

3. Graf B., Gook S.E., Gumenyuk A.V., Retmaier M. Combined laser additive technologies for the production of turbine blades of complex geo-metric shapes. Global'naya yadernaya be-zopasnost'. 2016; 3(20):34–42. (In Russ.).

4. Sghaier T.A.M., Sahlaoui, Mabrouki T., Sal-lem H., Rech J. Selective Laser Melting of Stainless-Steel A Review of Process, Micro-structure, Mechanical Properties and Post-Processing treatments. International Journal of Material Forming. 2023;16(4):1–12.

5. https://doi.org/10.1007/s12289-023-01769-w

6. Nandhakumar R., Venkatesan K. A process parameters review on Selective laser melting-based additive manufacturing of Single and Multi-Material: Microstructure, Properties, and machinability aspects. Materials Today Communications. 2023;35(9-10).

7. https://doi.org/10.1016/j.mtcomm.2023.105538

8. Lu J., Zhuo L. Additive manufacturing of ti-tanium alloys via selective laser melting: Fab-rication, microstructure, post-processing, per-formance and prospect. International Journal of Refractory Metals and Hard Materials. 2023;111(8). https://doi.org/10.1016/j.ijrmhm.2023.106110

9. Song X., Zhang Y. Progress of high-entropy alloys prepared using selective laser melting. Science China Materials. 2023;66:4165–4181.

10. Chen X., Wen K., Mu W., Zhang Y., Shan Huang, Liu W. Effect of layer-by-layer laser remelting process on the microstructure and performance of selective laser melting 316L stainless steel. The International Journal of Advanced Manufacturing Technology. 2023;128:2221–2236.

11. Bouabbou A., Vaudreuil S. Understanding la-ser-metal interaction in selective laser melting additive manufacturing through numerical modelling and simulation: a review. Virtual and Physical Prototyping. 2022;17:543–562. https://doi.org/10.1080/17452759.2022.2052488

12. Khan, H.M., Waqar, S., Koç, E. Evolution of temperature and residual stress behavior in se-lective laser melting of 316L stainless steel across a cooling channel. Rapid Prototyping Journal. 2022;28(7):1272‒1283.

13. https://doi.org/10.1108/RPJ-09-2021-0237

14. Zhang C., Zheng H., Yang L., Li Y., Jin J., Cao W., Yan Ch., and Sh Y. Mechanical responses of sheet-based gyroid-type triply periodic mini-mal surface lattice structures fabricated using selective laser melting. Materials & Design. 2022;214. https://doi.org/10.1016/j.matdes.2022.110407

15. Zhai W., Zhou W., Zhu Z. Selective Laser Melting of 304L and 316L Stainless Steels: A Comparative Study of Microstructures and Mechanical Properties. Steel Research interna-tional. 2022;93(7).

16. https://doi.org/10.1002/srin.202100664

17. Waqar S., Guo K., Sun J. Evolution of residu-al stress behavior in selective laser melting (SLM) of 316L stainless steel through pre-heating and in-situ re-scanning techniques. Optics & Laser Technology. 2022;149:107806. https://doi.org/10.1016/j.optlastec.2021.107806

18. Uçak N., Çiçek A., Aslantaş K. Machinability of 3D printed metallic materials fabricated by selective laser melting and electron beam melting: A review. Journal of Manufacturing Processes. 2022;80(9):414–457.

19. https://doi.org/10.1016/j.jmapro.2022.06.023

20. Yao D., Wang J., Li M-P., Zhao T., Cai Y., An X., Zou, R., Zhang H., Fu H., Yang X., Zou Q. Segregation of 316L stainless steel powder during spreading in selective laser melting based additive manufacturing. Powder Tech-nology. 2022;397:117096–117096.

21. https://doi.org/10.1016/j.powtec.2021.117096

22. Gatões D., Alves R., Alves B., Vieira M.T. Se-lective Laser Melting and Mechanical Proper-ties of Stainless Steels. Materials. 2022;15(21). https://doi.org/10.3390/ma15217575

23. Galinovskii A.L., Filimonov A.S., Rogalev R.S., Sveshnikov A.S., Kra-vchenko I.N., Orlov M.A. Re-search of materials databases for selective laser melting technology. Elektrometallurgiya. 2022;3:18–27. EDN: TABTZE. (In Russ.). https://doi.org/10.31044/1684-5781-2022-0-3-18-27

24. Afanas'eva L. E., Izmailov V.V., Novoselova M.V. Surface roughness of stainless steel samples obtained by selective laser melting technolo-gy. Mekhanika i fizika protsessov na poverkh-nosti i v kontakte tverdykh tel, detalei tekhno-logicheskogo i energeticheskogo oborudovani-ya. 2021;14:62–66. EDN: PTMGXO. (In Russ.).

25. To M.Kh., Safonov E.V., Adylina A.P., Ovchinnikov V.V. Mechanical properties and microstructure of 12X18N10T steel obtained by selective laser melting. Zagotovitel'nye proizvod-stva v mashinostroenii. 2022;20(6):282–287. EDN: OAYGSJ. (In Russ.). https://doi.org/10.36652/1684-1107-2022-20-6-282-287

26. Zel'dovich V.I., Khomskaya I.V., Kheifets A.E., Abdullina D.N. Structural changes dur-ing heating in austenitic stainless steel pro-duced by selective laser melting. Fizika metal-lov i metallovedenie. 2022;123(9):971–977. EDN: KRARUS. (In Russ.).

27. https://doi.org/10.31857/S0015323022090133

28. Krivilev M.D., Kharanzhevskii E.V., Kamaeva L.V., Zakirova R.M. Analysis of residual stress lev-els in compact 316L steel specimens produced by selective laser melting. In: Bernstein Read-ings on Thermomechanical Processing of Me-tallic Materials: Collection of Abstracts. Scien-tific and Technical Seminar. October 25-27, 2022. Moscow: Natsional'nyi issledovatel'skii tekhnologicheskii universitet «MISIS», 2022:82. EDN: IZCBUI. (In Russ.).