Tula State University (Tula, Russia):

A. A. Malikov, Dr. Eng., Prof., Dept. “Machinebuilding Technology”
E. V. Markova, Cand. Eng., Associate Prof., Dept. “Machinebuilding Technology”, e-mail: marta06@yandex.ru
N. B. Fomicheva, Cand. Eng., Associate Prof., Dept. “Metal Physics and Material Science”
O. V. Chechuga, Cand. Eng., Associate Prof., Dept. “Machinebuilding Technology”

This paper presents the results of studies of friction surfaces and the microstructure of the surface layer, after hardening by electrotechnologies to select the method of surface treatment of steel, providing a high hardening effect. The characteristic areas of the surface relief of structural steels hardened by different methods 30ХГСН2А and 30ХРA after wear under sliding friction without lubricant were analyzed. It is found that different types of hardening on the basis of electrical technologies, including electroerosion and electron beam treatment create a different hardening effect in steels and are characterized by different friction surfaces. Electroerosion treatment in the mode of productive removal is characterized by the greatest hardening effect for the studied steel grades. The surface after electron-beam hardening is characterized at the microscopic level by the appearance of contrasting friction tracks, as well as fragmentary reliefs with noticeable damage. The microstructural analysis showed the influence of the type of treatment on the structural characteristics of the material. During electroerosion treatment, a characteristic white layer with increased microhardness is formed on the surface. The combination of hardening on the basis of the scheme of electrical discharge machining reduces the microhardness of both steels and reduces the thickness of the white layer. Electron beam treatment generates three-zone structure as 30ХРA for steel and for steel 30ХГСН2А.

1. Nosov N. V., Shilova Yu. А., Lysenko N. V. Physical and mechanical state of a surface layer during the final abrasive machining of friction surfaces. Izvestiya Samarskogo nauchnogo tsentra Rossiyskogo akademii nauk. 2016. pp. 303–310.
2. Ablyaz Т. R. Analysis of the part`s processed surface quality after EDM processing. Sovremennye problemy nauki i obrazovaniya. 2014. No. 2. pp. 58–62.
3. Blinova Т. А., Puzacheva Е. I., Boyko А. F. Improving the accuracy of EDM processing. Proceedings of the II International scientific and practical conference «Perspective development of science, technology and technology». Vol. 1. Kursk: YuZGU, 2012. pp. 89–90.
4. Aleksandrova Е. S., Ivanova А. М. Fractographic study of fractures of specimens from hardened low-alloyed steel after low-cycle tests. Nauka i obrazovanie. 2016. No. 1. pp. 77–82.
5. Radyuk A. G., Gorbatyuk S. M., Gerasimova A. A. Use of electric-arc metallization to recondition the working surfaces of the narrow walls of thick-walled slab molds. Metallurgist. 2011. Vol. 55. Nos. 5-6. pp. 419–423.
6. Bergmann M., Kainz A., Zeman K., Krimpelstaetter K., Paesold D., Smeulders B., Schellingerhout P. Enhanced modelling of friction and lubrication in cold strip rolling. Proc. 9^th Intern. and 6th Europ. Rolling Conf. Venedig, Italien, 10−12 Juni 2013.
7. Gerasimova А. А., Radyuk А. G. Improvement of billet surface quality via coating application. Chernye Metally. 2015. No. 3.
8. Dagani R. Individual Surface Atoms Identified, Chemical & Engineering News. Published by American Chemical Society. 5 March 2007. p. 13.
9. Chubukov M. Yu., Rutskii D. V., Uskov D. P., Zyuban N. А., Palatkina L. V. Influence of service life of piercing mill plugs on structure and composition of surface layers. Chernye Metally. 2016. No. 11. pp. 114–122.
10. Straffelini G. Friction and wear. Methodologies for Design and Control. Springer Intern. Publ. Switzerland, Cham, 2015.
11. Wirz R. Е. Discharge plasma processes of ring-cusp ion thrusters: In partial fulfillment of the requirements for the degree of Doctor of Philosophy. Pasadena, California: CA Inst, of Technology, 2005.
12. Bergmann М., Krimpelstaetter К., Smeulders B., Schellingerhout P., Paesold D., Strasser D., Kainz А., Zeman К. Expanded tribological simulation in cold rolling of sheet metal. Chernye Metally. 2017. No. 11. pp. 48–55.