Formation of A Hardened Surface Layer Under Complex Laser Action on the Cutting Edge of Parts Made of Structural Carbon Steels

The purpose of the work was to study the effect of laser modification of the cutting edge on changes in the structure and mechanical properties of the surface layer of parts made of hot–rolled structural carbon steels of grades 20, 35, 45 using a fiber laser.
Methods. Structural carbon steels of grades 20, 35, 45 were selected as the objects of the study. To study the effect of laser modification on changes in the structure and mechanical properties of machine parts using laser cutting, special samples were made in the form of plates with a thickness of 2 mm (st20 and st45) and 4 mm (st35). After gas laser cutting, laser modification of the Q-switch cutting edge was performed with a fiber pulsed laser.
Results. The regularities of changes in the structure of the zone of gas-laser thermal exposure after laser treatment (cutting, modification) are revealed. It has been established that repeated laser treatment (laser modification) of the cutting edge does not lead to a change in the structural components and microhardness in the zone of gas-laser thermal effects obtained after laser cutting. It has been established that the nature of the microhardness change is the same for all the studied steel grades: the highest values are reached near the surface of gas-laser treatment and are, for example, for steel grade 35 470-560 HV, which is 3,2-3,9 times greater than the initial microhardness (145 HV). Thus, a hardened layer with increased wear resistance is formed on the surface of the part after laser treatment. It is shown that the use of laser surface modification as an additional operation in the manufacture of parts by laser cutting makes it possible to improve the quality (roughness) of the surface layer. At the same time, the greatest effect of reducing roughness is given by laser modification in three passes along the X-Y plane.
Conclusion. The results obtained can be used in the creation of resource-saving material processing processes.

1. Kovalenko V. S., Golovko L. F., Merkulov G. V., Strizhak A. I. Uprochnenie detalei luchom lazera [Hardening of parts with a laser beam]; ed. by V. S. Kovalenko. Kyiv, Tekhnika Publ., 1981. 131 p.

2. Sergeev N. N., Sergeev A. N., Gvozdev A. E., Grashkin I. P., Minaev I. V., Polosin S. I., Tikhonova I. V., Cheglov A. E., Khonelidze D. M. Kompleks nauchno-tekhnicheskikh, proektnokonstruktorskikh i tekhnologicheskikh razrabotok po sozdaniyu, izgotovleniyu i vnedreniyu vysokotochnogo importozameshchayushchego oborudovaniya kachestvennoi lazernoi i gazoplazmennoi obrabotki listovogo prokata [A complex of scientific and technical, design and technological developments for the creation, manufacture and implementation of high-precision import-substituting equipment for high-quality laser and gas-plasma processing of sheet metal]; ed. by N. N. Sergeev. Tula, TulSU Publ., 2014. 188 p.

3. Veiko V. P., Kishalov A. A., Mutin T. Y., Smirnov V. N. Perspektivy industrial'nykh primenenii lazernoi ochistki materialov [Prospects of industrial applications of laser cleaning of materials]. Nauchno-tekhnicheskii vestnik informatsionnykh tekhnologii, mekhaniki i optiki = Scientific and Technical Bulletin of Information Technologies, Mechanics and Optics. 2012, no. 3 (79), pp. 50–54.

4. Suslov A. G. Kachestvo poverkhnostnogo sloya detalei mashin [The quality of the surface layer of machine parts]. Moscow, Mashinostroenie Publ., 2000. 320 p.

5. Veiko V. P., Smirnov V. N., Chirkov A. M., Shakhno E. A. Lazernaya ochistka v mashinostroenii i priborostroenii [Laser cleaning in mechanical engineering and instrumentation]. St. Petersburg, ITMO Research Institute, 2013. 103 p.

6. Veiko V. P., Mutin T. Y., Smirnov V. N., Shakhno E. A., Batishche S. A. Lazernaya ochistka poverkhnostei metallov: fizicheskie protsessy i primenenie [Laser cleaning of metal surfaces: physical processes and applications]. Izvestiya vyshchikh uchebnykh zavedenii. Priborostroenie = Proceedings of Higher Educational Institutions. Instrumentation, 2008, vol. 51, no. 4, pp. 30–36.

7. Lu Y. F., Ren Z. M. Laser microprocessing and the applications in microelectronics industry [Laser microprocessing and the applications in microelectronics industry]. Proc. SPIE, 2000, vol. 4157, pp. 191–199.

8. Minaev I. V., Sergeev N. N., Tikhonova I. V., Gvozdev A. E., Khonelidze D. M., Golyshev I. V. Vliyanie parametrov lazernoi rezki na kachestvo poverkhnosti reza stal'nykh listov [The influence of laser cutting parameters on the quality of the cutting surface of steel sheets]. Izvestiya Tul'skogo gosudarstvennogo universiteta. Tekhnicheskie nauki = Izvestiya Tula State University. Technical sciences, 2014, is. 3, pp. 50–58.

9. Gvozdev A. E., Golyshev I. V., Minaev I. V., Sergeev A. N., Sergeev N. N., Tikhonova I. V., Khonelidze D. M., Kolmakov A. G. Mnogoparametricheskaya optimizatsiya parametrov lazernoi rezki stal'nykh listov [Multiparametric optimization of parameters of laser cutting of steel sheets]. Materialovedenie = Materials Science, 2015, no. 2, pp. 31–36.

10. Gvozdev A. E., Sergeev N. N., Minaev I. V., Kolmakov A. G., Tikhonova I. V., Sergeev A. N., Provotorov D. A., Khonelidze D. M., Maliy D. V., Golyshev I. V. Raspredelenie temperatur i struktura v zone termicheskogo vliyaniya dlya stal'nykh listov posle lazernoi rezki [Temperature distribution and structure in the zone of thermal influence for steel sheets after laser cutting]. Materialovedenie = Materials Science, 2016, no. 9, pp. 3–7.

11. Sergeev N. N., Minayev I. V., Gvozdev A. E., Cheglov A. E., Tikhonova I. V., Gubanov O. M., Tsyganov I. A., Alyavdina E. S., Breki A. D. Vliyanie soderzhaniya ugleroda i parametrov lazernoi rezki na stroenie i protyazhennost' zony termicheskogo vliyaniya stal'nykh listov [Influence of carbon content and parameters of laser cutting on the structure and length of the heataffected zone of steel sheets]. Stal' = Staly, 2018, no. 5, pp. 21–26.

12. Sergeev N. N., Minaev I. V., Tikhonova I. V., Gvozdev A. E., Kolmakov A. G., Sergeev A. N., Kutepov S. N., Maliy D. V. Metodologiya vybora rezhimov lazernoi rezki listov iz konstruktsionnykh stalei dlya obespecheniya trebuemogo kompleksa pokazatelei kachestva poverkhnosti [Methodology for selecting modes of laser cutting of sheets from structural steels to ensure the required set of indicators of surface quality]. Materialovedenie = Material Science, 2019, no. 10, pp. 25–32.

13. Minaev I. V., Tikhonova I. V., Gvozdev A. E., Kolmakov A. G., Arkhipova E. A. Formirovanie poverkhnosti reza i poverkhnostnoe uprochnenie pri lazernoi rezke zvezdochek tsepnykh peredach iz stalei ST3 i 30KhGSA [Formation of the cut surface and surface hardening during laser cutting of chain gear sprockets from ST3 and 30KhGSA steels]. Deformatsiya i razrushenie materialov = Deformation and destruction of materials, 2020, no. 9, pp. 16–21.

14. Minaev I. V., Gvozdev A. E., Kutepov S. N., Klementyev D. S., Kalinin A. A. Osobennosti stroeniya zony gazolazernogo termicheskogo vliyaniya konstruktsionnykh legirovannykh stalei marok 09G2S i 20Kh13 [Features of the structure of the zone of gas-laser thermal influence of structural alloy steels of grades 09G2S and 20Kh13]. Izvestiya Tul'skogo gosudarstvennogo universiteta. Tekhnicheskie nauki = Izvestiya Tula State University. Technical Sciences, 2022, Is. 10, pp. 499–506.

15. Veiko V. P., Libenson M. N., Chervyakov G. G., Yakovlev E. B. Vzaimodeistvie lazernogo izlucheniya s veshchestvom, silovaya optika [Interaction of laser radiation with matter, power optics]. Moscow, Fizmatlit Publ., 2008. 312 p.

16. Vedernikova I. I., Poletaev V. A. Uprochnenie rabochikh poverkhnostei detalei mashin lazernym modifitsirovaniem [Hardening of working surfaces of machine parts by laser modification]. Vestnik Ivanovskogo gosudarstvennogo energeticheskogo universiteta = Bulletin of the Ivanovo State Power Engineering University, 2008, is. 3, pp. 1–3.

17. Korneev V. V., Kosyrev F. K., Moryashchev S. F. O nekotorykh zavisimostyakh termoobrabotki lazerom [On some dependencies of laser heat treatment]. Fizika i khimiya obrabotki materialov = Physics and chemistry of materials processing, 1980, no. 36, pp. 32–33.

18. Spiridonov N. V., Kobyakov O. S., Kupriyanov I. L. Plazmennye i lazernye metody uprochneniya detalei mashin [Plasma and laser methods of hardening machine parts]. Minsk, Vysheysh. shk. Publ., 1988. 155 p.

19. Kraposhin V. S., Shakhlevich K. P., Vyazemsky M. G. Vliyanie lazernogo nagreva na kolichestvo ostatochnogo austenita v stalyakh i chugunakh [The effect of laser heating on the amount of residual austenite in steels and cast irons]. Metallovedenie i termicheskaya obrabotka metallov = Metal Science and heat treatment of metals, 1989, no. 10, pp. 21–23.

20. Voitovich О. N., Sokorov I. О. Issledovanie vliyaniya parametrov lazernoi termoobrabotki na svoistva uprochnennykh poverkhnostnykh sloev [The research into the influence of laser thermal processing parameters on the properties of strengthened surface layers]. Vestnik Belorussko-Rossiiskogo universiteta = Bulletin of the Belarusian-Russian University, 2013, no. 2 (39), pp. 6–14.