Obrabotka Metallov 2019 Vol. 21 No. 2

OBRABOTKAMETALLOV Vol. 21 No. 2 2019 16 TECHNOLOGY References 1. Black J.T., Kohser R.A. DeGarmo’s materials and processes in manufacturing . NewYork, John Wiley & Sons, 2011. 1184 p. ISBN 0470924675. 2. Jones F.D. Thread-cutting methods: a treatise on the operation and use of various tools and machines for forming screw threads, including the application of lathes, taps, dies, standard and special attachments, thread-milling machines, and thread-rolling machines. Sacramento, Creative Media Partners, 2018. 358 p. ISBN-10: 066644692X. ISBN-13: 9780666446923. Single Pass Formation of Threads on Ductile Metals by Deformational Cutting Nikolai Zubkov a, * Bauman Moscow State Technical University, 5 Baumanskaya 2-ya, Moscow, 105005, Russian Federation a http://orcid.org/0000-0003-3757-1299, zoubkovn@bmstu.ru Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2019 vol. 21 no. 2 pp. 6–17 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2019-21.2-6-17 Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov ARTICLE INFO Received: 15 March 2019 Revised: 08 April 2019 Accepted: 17 April 2019 Available online: 15 June 2019 Keywords : Thread Threading Thread cutter Threaded profile Deformational cutting Funding This work was supported by the Ministry of Education and Science of Russia (Grant № 9.5617.2017/VU). Acknowledgements The author are grateful to Evgenij Log- inov for the help in carrying out experi- ments and Alexander Ovchinnikov for discussion of the received results. ABSTRACT Introduction. Threads manufacturing in mass production is based on non-waste methods of plastic deformation. For medium-and small-scale production, methods of thread cutting with taps, dies, thread chasers, thread mills, thread cutters have become widespread. For all known methods of thread cutting, the problem is to obtain threads on the material with high plasticity, especially on thin-walled tubes. A universal method of obtaining threads of various diameters and pitches is threading on lathes using thread cutters. A significant disadvantage of threading by cutters is the multi-pass processing, which significantly reduces productivity. There is a relatively new method of deformational cutting (DC) based on both the cutting process and the process of deformation of the undercut layer. In the article, the modification of the DC method is considered as an alternative to the traditional cutter threading based on the material removal from the thread grooves. The purpose of the work: approbation of the DC method as a method of obtaining threads on ductile metals in one pass of the tool with a minimum amount of material to be removed as a chip. The tasks of the work: theoretical analysis of the process of redistribution of material in the process of DC, identification of the main laws and features of thread formation, analysis of the threads obtained. In this paper, the outer threading of copper tubes by the DC method but having tool feed to the deforming edge is studied. Methods of research are the analysis of geometric parameters obtained threads and metallographic studies, including the measurement of the distribution of hardness on the threaded profile. Results and discussion. For DC uses a special tool that provides the cutting process of the main cutting edge, and eliminates the cutting process on the auxiliary edge, which is deforming edge. In DC process the layer cut by the cutting edge is squeezed out onto the treated surface in the form of a ridge, which takes the final shape of the threaded profile on the next turn of the workpiece. Conclusions: Theoretically justified and experimentally confirmed the designation of processing parameters to obtain a threaded profile of the required geometry. The proposed method of obtaining threads mediate between the methods based on the cutting process (removal of the workpiece material) and the process of plastic deformation. The main difference from conventional thread cutting is that in the process of DC there is a plastic redistribution of the material from the volume of the thread grooves to the volume of the thread ridge. The main difference from the thread rolling is that in DC new surfaces are formed, which is peculiar for the cutting processes. In the structure of the material of the threaded profile there are zones common for both processes of plastic deformation and conventional cutting. The large value of tool rake angle on the cutting edge and improved metal flow conditions on the tool face significantly reduce the load on the workpiece to be processed. In contrast to grooving with a threaded cutter, the proposed process allows threading in a single pass of the tool. In practical terms , the method can be used for single-pass cutting of threads with a cutter on ductile metal. For citation: Zubkov N.N. Single pass formation of threads on ductile metals by deformational cutting. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science , 2019, vol. 21, no. 2, pp. 6–17. DOI: 10.17212/1994-6309-2019-21.2-6-17. (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