Ogneva T.S. et. al. 2018 Vol. 20 No. 2

OBRABOTKAMETALLOV Vol. 20 No. 2 2018 141 MATERIAL SCIENCE References 1. Silman G.I., Kamynin V.V., Goncharov V.V. On the mechanisms of copper effect on structure in cast iron. Metal Science and Heat Treatment , 2007, vol. 49, iss. 7–8, pp. 387–393. doi: 10.1007/s11041-007-0072-z. Structure and Properties of Heat-treated Medium-carbon Steels Alloyed with Copper Tatyana Ogneva 1, a,* , Nikita Martyushev 2, b , Iris Altpeter 3, c Mikhail Surkov 2, d , Alexandr Tokarev 4, e , Tatyana Krutskaya 5, f 1 Novosibirsk State Technical University, 20 Prospekt K. Marksa, Novosibirsk, 630073, Russian Federation 2 National Research Tomsk Polytechnic University, 30 Lenin Avenue, Tomsk, 634050, Russian Federation 3 Fraunhofer Institute for Non-Destructive Testing IZFP, Campus E3 1, Saarbrucken, 66123, Germany 4 Siberian State University of Water Transport, 33 Schetinkina st., Novosibirsk, 630099, Russian Federation 5 Novosibirsk State University of Architecture and Civil Engineering, 113 Leningradskaya st., Novosibirsk, 630008, Russian Federation a https://orcid.org/0000-0002-0081-283X , ogneva@corp.nstu.ru , b https://orcid.org/0000-0003-0620-9561, martjushev@tpu.ru, c https://orcid.org/0000-0002-3006-625X , irisaltpeter@mail.ru , d https://orcid.org/0000-0002-3654-8401, masur@tpu.ru, e https://orcid.org/0000-0002-2841-3689, aot51@ngs.ru , f https://orcid.org/0000-0001-8003-4523, j_krutskii@rambler.ru Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2018 vol. 20 no. 2 pp. 130–143 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2018-20.2-130-143 ARTICLE INFO Article history : Received: 15 March 2018 Revised: 02 April 2018 Accepted: 30 April 2018 Available online: 15 June 2018 Keywords : Steel Alloying with copper Quenching Structure Wear resistance ε-Cu nanoparticles Funding: This work is supported by the Russian Science Foundation under grant No. 15-19-00230. ABSTRACT Introduction. Copper alloyed steel is considered to be a possible alternative to expensive bronze in the manu- facture of large-sized parts of heavy-duty sliding friction units. The operating conditions of these units assume the presence of large specific loads. Thus, the materials for its production should have a high complex of strength and tribological properties. Quenched iron-carbon steels have the greatest strength, however, nowadays, the issue of the effect of copper on the structure and properties of medium-carbon steels after quenching remains open. The purpose of the work: to study the structure, strength and tribotechnical properties of cast medium-carbon steel, alloyed with copper (0... 9 wt. %), after quenching from 800, 900, 1000 and 1150 °C and low tempering at 200 °C. The methods of investigation. Structural studies were performed using optical metallography, scanning electron microscopy and X-ray phase analysis. The mechanical properties of alloys after casting and quenching with low tempering were studied, the hardness of the Rockwell materials was evaluated, and the wear resistance test was carried out on fixed and non-rigidly fixed abrasive particles. Results and discussion. With the increase of copper content in the steel the size of the ferritic grains decreases and the dispersion of perlite increases. The nanosized inclusions of the copper ε-phase formed in the ferrite matrix were studied by transmission electron microscopy. Heating up to 800 °C doesn’t provide an opportunity for complete quenching of steels alloyed with copper. In addition to martensite, the micro- volumes of ferrite and perlite are present in the structure of alloys. Quenching from 900 °C leads to the formation of a completely martensitic structure. A further increase in the quenching temperature doesn’t lead to a qualitative change in the structural composition. Inclusions of the copper phase predominantly have a shape close to spherical. However, after quenching from 1150 °С in an alloy with 9% copper, the ε-Cu inclusions precipitates as a thin films along the former boundaries of austenitic grains. The TEM investigations showed that heating for quenching leads to dissolution of copper nanosized inclusions. At the fast cooling stage, copper in the form of inclusions is not released. Alloying with copper up to 6 wt. % provides the growth of tribotechnical characteristics of medium-carbon steels. It was found that samples quenched from 900 °C have the highest complex of mechanical properties. For citation: Ogneva Т.S., Martushev N.V., Altpeter I., Surkov M.A., Tokarev А.О., Krutskaya Т.М. Structure and properties of heat-treated medium-carbon steels alloyed with copper. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science , 2018, vol. 20, no. 2, pp. 130–143. doi: 10.17212/1994-6309-2018-20.2-130-143. (In Russian). ______ * Corresponding author Ogneva Tatyana S. , P h.D. (Engineering), Associate Professor Novosibirsk State Technical University, 20 Prospekt K. Marksa, 630073, Novosibirsk, Russian Federation Tel.: 8 (383) 315-29-01, e-mail: ogneva@corp.nstu.ru Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov