Obrabotka Metallov 2020 Vol. 22 No. 2

OBRABOTKAMETALLOV Vol. 22 No. 2 2020 27 TECHNOLOGY The Effect of Ultrasonic Impact-Friction Treatment on a Surface Roughness of 09Mn2Si Structural Steel Nikita Lezhnin 1, a,* , Alexey Makarov 1, b , Sergey Luchko 1, c , Boris Loginov 2, d , Artem Loginov 3, e 1 M.N. Miheev Institute of Metal Physics of the Ural Branch of the Russian Academy of Sciences, 18 So fi a Kovalevskaya st., Yekaterinburg, 620219, Russian Federation 2 National Research University of Electronic Technology - MIET, Bld. 1, Shokin Square, Zelenograd, Moscow, 124498, Russian Federation 3 Lomonosov Moscow State University, GSP-1, Leninskie Gory, Moscow, 119991, Russian Federation a https://orcid.org/0000-0001-9483-6607, nlezhnin@bk.ru , b https://orcid.org/0000-0002-2228-0643, avm@imp.uran.ru , c https://orcid.org/0000-0002-2368-0913, serojaluchko@gmail.com, d https://orcid.org/0000-0001-5081-1424, b-loginov@mail.ru, e https://orcid.org/0000-0003-2090-5301, loginov.ab15@physics.msu.ru Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2020 vol. 22 no. 2 pp. 16–29 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2020-22.2-16-29 Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov ARTICLE INFO Article history : Received: 20 March 2020 Revised: 20 April 2020 Accepted: 11 May 2020 Available online: 15 June 2020 Keywords : Surface strain hardening Ultrasonic impact treatment Surface roughness Structural steel Funding The research was carried out within the state assignment of Ministry of Education and Science of the Russian Federation on themes No. АААА - А 18-118020190116-6, sup- ported by RFBR (project No. 18-38- 00868). ABSTRACT Introduction. Ultrasonic impact-frictional treatment (UIFT) is a new method of surface strain hardening that improves the properties and re fi nes the microstructure of the surface layer of metallic material. Unlike traditional ultrasonic impact treatment (UIT), the UIFT applies impacts with ultrasonic frequency at an acute angle α to the metal surface in order to activate the shear deformation mode. Oxygen-free atmosphere of argon enhances friction and prevents embrittlement of the diffusion-active deformed layer. Adecrease of the angle α during the UIFT leads to a shift of the metal displaced by the tool towards the impact. Therefore, the tool position, oscillating with an ultrasonic frequency, with respect to the tool trajectory may have a profound effect on the surface microrelief. Objective is studying the in fl uence of the impact direction on the roughness and hardening degree of the 09Mn2Si structural steel surface regarding the tool cross-feed during UIFT at an angle α = 50º in the argon medium. Research Methods are following: microhardness measurements, atomic force microscopy (AFM), optical pro fi lometry, optical microscopy and scanning electron microscopy with EBSD analysis. Results and discussion. After grinding, the steel surface microhardness is 200 HV0.1 and the arithmetic mean deviation of the surface pro fi le is Ra = 0.6 μ m. UIT at an angle α = 90º in an industrial oil medium results in the surface hardening up to 260 HV0.1, while the Ra parameter increases to 1.6 μ m. UIFT with the impact vertical deviation towards the specimen cross-feed (forehand) provides a relatively uniform microrelief with Ra= 0.4 μ m and the deformed layer microhardness of up to 500 HV0.1. The tool deviation in the contrary direction towards the specimen cross-feed (backhand) increases the surface hardening degree (620 HV0.1), but leads to the formation of an advanced microrelief consisting of shifted metal displaced by the tool, as well as to the Ra parameter increase up to 3.5 μ m. At the same time, the submicrorelief roughness remains approximately at the same level (Ra= 0.03–0.04 μ m) for all three hardening treatment methods. Thus, the angle and impact direction during ultrasonic hardening treatment are important technological parameters that allow long-range controlling of the surface microrelief with the UIFT applied as a fi nishing hardening treatment. UIFT is an effective method of surface hardening, intended to form a surface even with a lower roughness of the micropro fi le compared to that of a traditional grease-applied UIT. ______ * Corresponding author Lezhnin Nikita V. , Ph.D. (Engineering), Senior Researcher M.N. Mikheev Institute of Metal Physics of the UB RAS, 18 S. Kovalevskaya St., Ekaterinburg, 620108, Russian Federation Tel.: +7-919-385-65-92, e-mail: nlezhnin@bk.ru For citation: Lezhnin N.V., Makarov A.V., Luchko S.N., Loginov B.A., Loginov A.B. The effect of ultrasonic impact-friction treatment on a surface roughness of 09Mn2Si structural steel. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science , 2020, vol. 22, no. 2 , pp. 16–29. DOI: 10.17212/1994-6309-2020-22.2-16-29. (In Russian).