Obrabotka Metallov 2018 Vol. 20 No. 2

OBRABOTKAMETALLOV Vol. 20 No. 2 2018 47 TECHNOLOGY References 1. Rajan T.V., Sharma C.P., Sharma A. Heat treatment principles and techniques. Delhi, India, PHI Learning, 2011. 408 p. ISBN 812030716X. Features of Quench Deformational Cutting Nikolai Zubkov 1 , a, * , Sergei Vasil’ev 1 , b , Victor Poptsov 2, c 1 Bauman Moscow State Technical University, 5 Baumanskaya 2-ya, Moscow, 105005, Russian Federation 2 LLC “Seco Tools”, 3 Malaya Gruzinskaya st., Moscow, 123242, Russian Federation a http://orcid.org/0000-0003-3757-1299, zoubkovn@bmstu.ru , b http://orcid.org/0000-0002-8882-4893, sergv@bmstu.ru , c http://orcid.org/0000-0002-8938-8210, poptsov-v.v@yandex.ru Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2018 vol. 20 no. 2 pp. 35–49 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2018-20.2-35-49 ARTICLE INFO Article history : Received: 12 March 2018 Revised: 29 March 2018 Accepted: 25 April 2018 Available online: 15 June 2018 Keywords : Quench deformational cutting surface hardening structural and phase transition hardness wear resistance heat rating Funding : This work was supported by the Ministry of Education and Science of Russia (Grant № 9.5617.2017/VU). ABSTRACT Introduction. An effective method of increasing the wear resistance of machine parts is surface hardening. The direct use of metal-cutting equipment to heat the material of the part in the process of abrasive or edge cutting machining is a new promising direction in surface hardening methods. The heating of the surface is achieved in the cutting process due to plastic deformation and friction between the tool and the workpiece and is accompanied by a chip separation. There is also a relatively new method of deformational cutting (DC), which is based on both the cutting process and the targeted deformation of the cut layers. In contrast to the known methods of hardening the surface by turning or grinding, DC hardening is made without separation of the workpiece material as chips. The clipped layer remains on the surface in the form of tightly stacked layers firmly attached to the base. The aim of the work: testing the DC as a method of surface quenching, as well as the identification of the basic laws and features of such surface hardening. The hardened layers on the outer surface of steel samples obtained by the quench DC (QDC) with the thickness of the hardened layer up to 0.6 mm on steel 20, 35, 40Kh are invesigated . Research methods are metallographic tests of hardened structures, including the distribution of hardness, measurement of forces and temperature QDC and tribological tests. Results and discussion. For QDC the special tool is used, providing process of cutting by the main cutting edge and excluding process of cutting on an auxiliary edge. At QDC the undercut layers are intensively deformed, heated and after that cooled by heat transfer into the core of the workpiece. This leads to the formation of hardened inclined thin fins on the surface, having a strong bond with the base and tightly pressed against each other. In the article it is shown that at QDC temperature of the undercut layer sufficient for structural and phase transformations in steels is reached. It is established that the rate of heating is up to two million degrees Celsius per second at ultra-high degrees and rates of strain accompanying the QDC process. These conditions and high cooling rates lead to the formation of non-equilibrium nanostructures with increased hardness and wear resistance. The paper shows the possibility of obtaining quench structures with a thickness of the hardened layer up to 1 mm, including those consisting of alternating inclined layers of different hardness, similar in structure to Damascus steel. The exponential decrease in the hardness across the thickness of the hardened layer, common to all methods of surface hardening for QDC is not observed. The method of QDR has a unique ability to influence the material of the workpiece, comparable with the explosive processes in power density, developed pressures and heating rates. The samples are hardened, by QDC showed the advantages in wear resistance in comparison with samples of bulk hardening. Surface hardening of the part using the QDC method is economically feasible, because it has high performance, low power consumption and allows to abandon the traditional heat treatment operations that require expensive special equipment. For citation: Zubkov N.N., Vasil’ev S.G., Poptsov V.V. Features of quench deformational cutting. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science , 2018, vol. 20, no. 2, pp. 35–49. doi: 10.17212/1994-6309-2018-20.2- 35-49. (In Russian). ______ * Corresponding author Zubkov Nikolai N. , D.Sc. (Engineering), Professor Bauman Moscow State Technical University 5 Baumanskaya 2-ya, Moscow, 105005, Russian Federation Tel.: +7-916-607-7948, e-mail: zoubkovn@bmstu.ru Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov