Журналы →  Chernye Metally →  2019 →  №5 →  Назад

New developments of Tula State University
Название The interdependence of the substructure and wear resistance of surface-hardened structural steels
Автор L. M. Nechaev, N. B. Fomicheva, E. V. Markova
Информация об авторе

Tula State University (Tula, Russia):

L. M. Nechaev, Cand. Phys.-Math., Prof., Dept. “Theoretical Mechanics”, e-mail: nech47@yandex.ru
N. B. Fomicheva, Cand. Eng., Associate Prof., Dept. “Metal Physics and Material Science”
E. V. Markova, Cand. Eng., Associate Prof., Dept. “Machinebuilding Technology”


The results of metallographic researches and the study of wear resistance of 30KhN2MFA and 30KhGSA structural steels after hardening by such technologies as shot blasting, ultrasonic smoothing, laser processing, and electrochemical polishing have been presented. The evaluation of the tribotechnical properties of the hardened layers obtained by the investigated surface-hardening technologies have been carried out. The main criteria were the depth and type of substructural loosening of the active rubbing layer. An increase in the wear resistance of the material after the laser surface treatment was obtained. The paper presents the results of the calculation of the most important characteristics of the surface layer substructure: the level of microdeformations (Δа/а), dislocation density ρ, the size of the block structure fragments D after applying the tested hardening methods. The energy intensity of the structures was determined, which made it possible to identify structures with the highest fatigue life. It was established that the pulsed laser effect contributes to a sharp increase in the density of dislocations and micro-distortions. At the same time, the volume of the austenitic phase and the level of tensile macrostresses increase. Carrying out additional ultrasonic smoothing enables to reduce the amount of residual austenite and changes the sign of macrostresses. The combination of a pulsed laser and ultrasonic treatment to the greatest extent strengthens the structural steels under study.

Ключевые слова Laser treatment, wear resistance, shot blasting, ultrasonic smoothing, electrochemical polishing, micro-deformation, dislocation density, block structure
Библиографический список

1. Vlasov V. М., Nechaev L. М., Fomicheva N. B. Effect of forming deformation energy concentration on mechanical destruction of the coating. Uspekhi sovremennogo estestvoznaniya. 2002. No. 4. p. 103.
2. Vlasov V. М., Nechaev L. М., Fomicheva N. B. Predicting the functional capability of rubbing surfaces. Modern technologies in machine building: proceedings of 5th All-Russia scientific and practical conference. Part. 2. Penza, 2001. pp. 43–44.
3. Vlasov V. М., Nechaev L. М. Efficiency of high-strength thermal diffusion coatings in the friction units of machines. Tula: Priokskoe knizhnoe izdatelstvo, 1994. 237 p.
4. Arata Y., Mario H., Miyamoto I. Application of Laser for Material Processing. Heat Flow in Laser Hardening. Int. In-te Weld. Doc. 1978. Vol. IV. P. 241.
5. Liarokapis E., Anastassakis E. Laser induced thermal stains in isotropic media: Policrysaline Si. J. Appl. Phys. 1988. Vol. 63, No. 8. pp. 2615–2619.
6. Steen W., Courtney C. Laser Surface Treatment of En 8 Steels Using 2 kW CW-laser. Metals Tech. 1979. Vol. 6. No. 12. p. 456.
7. GOST 4543-2016. Structural alloy steel products. Introduced: 01.10.2017.
8. Welsh L. P., Tuchman J. A., Herman I. P. The impotence of thermal stresses and strains induced laser processing with focused Gaussian beams. Metals Tech. 1988. Vol. 64. No. 11. pp. 6274–6284.
9. Yashkova S. S. Laser surface hardening. Molodoy ucheny. 2017. No. 1. pp. 99–101.
10. Ablyaz Т. R. Analysis of quality of the part`s processed surface after EDM processing. Sovremennye problemy nauki i obrazovaniya. 2014. No. 2.

11. Ablyaz Т. R. The effect of wire-cut EDM processing on surface quality parameters. Tekhnologiya mashinostroeniya. 2014. No. 2. pp. 21–23.
12. GOST 9450-76. Measurements microhardness by diamond instruments indentation. Introduced: 01.01.1977.
13. Vodin D. V. Laser treatment as a promising method for improving the wear resistance of metal-cutting tools. Current issues of technical sciences: proceedings of the 3rd International scientific conference. Perm. April 2015. Perm: Zebra, 2015. 178 p.
14. Shastin V. I., Kargopoltsev S. К., Sitov I. S. Laser thermal strengthening of friction surfaces. Journal of advanced research in technical science. 2016. No. 1. pp. 5–13.
15. Drozdov Yu. N., Malenko P. I. Continual and discrete models of structural and phase transformations in the rubbing layers of materials. Problemy mashinostroeniya i avtomatizatsii. 2013. No. 3. pp. 55–57.

Language of full-text русский
Полный текст статьи Получить