Technology, energy, agriculture transport AIC

Vasyl Muzychuk – PhD, Associate Professor of the Department of “Technological Processes and Equipment of Processing and Food Productions” of the Vinnytsia National Agrarian University (3 Solnechnaya St, Vinnytsia, 21008, Ukraine, e-mail: wasil@vsau.vin.ua, https://orcid.org/0000-0002-0848-2943 ).

The article considers the process of forming the inner slot profile on a pipe billet by the method of cold plastic deformation, by compressing them with a matrix on a profile slotted mandrel (by the method of "covering" drawing). A comprehensive study of the mechanics of shaping products to assess their quality and study the possibility of improving the process itself.
In the case of three-dimensional molding, the surface of plasticity depends on the history of deformation, which is determined by the change in the stress state with increasing accumulated intensity of deformation. The surface of plasticity in this case is not fixed and can be constructed using the criterion of deformability, which provides the position of the point of the fracture surface, taking into account the history of deformation.  
The planes of deformation and boundary surfaces of plasticity are constructed, which showed a sufficient margin of plasticity for the process of forming the inner splined profile.
It is substantiated that when constructing the load trajectory in the space of dimensionless indicators   and   its type is unambiguously determined by the conditions of formation characteristic of the studied process and practically does not depend on the mechanical properties of the deformed metal.
The areas of deformation closest to the failure are determined by indicators that take into account the influence of the first and third invariants of the stress tensor (lateral region and area of depressions of the profile relative to the process of forming the internal splined profile), in which the used plasticity reaches values   = 0,34 ... 0,4.
From the point of view of providing a margin of safety, such calculations must be performed taking into account the indicator that takes into account the influence of the third invariant of the stress tensor.

[1]    Kolmogorov, V. L. (1970). Napryazheniye. Deformatsii. Razrusheniye [Voltage. Deformations. Destruction]. M: Metallurgy. [in Rassian].
[2]    Ogorodnikov, V. A., Sivak I. O. (1982). Issledovaniye protsessov slozhnogo deformirovaniya v malootkhodnoy tekhnologii ob"yomnoy shtampovki [Research of complex deformation processes in low-waste technology of forging]. Tr. Republic of NTK "Modern methods of low-waste and waste-free technology in mechanical engineering". Kishinev. 122–123. [in Belarus].
[3]    Ogorodnikov, V. A. (1983). Otsenka deformiruyemosti metallov pri obrabotke davleniyem [Assessment of the deformability of metals during pressure treatment]. K: Vyshcha shkola. [in Ukrainian].
[4]    Ogorodnikov, V. A. (1989).  Deformiruyemost' i razrusheniye metallov pri plasticheskom formoizmenenii. [Deformability and fracture of metals during plastic deformation]. К: UMK 130. [in Ukrainian].
[5]    Ohorodnikov, V. A., Muzychuk, V. I., Nakhaychuk, O. V. (2007). Mekhanika protsesiv kholodnoho formozminyuvannya z odnotypnymy skhemamy mekhanizmu deformatsiyi. Monohrafiya [Mechanics of cold forming processes with the same type of deformation mechanism schemes. Monograph]. V: UNIVERSUM-Vinnytsya [in Ukrainian].
[6]    Nakhaychuk, O. V., Rosenberg, O. O., Ogorodnikov, V. A., Kritsky, A. D., Melnichenko, V. V., Studenets, S. F. (2008). Novi tekhnolohichni protsesy z vykorystannyam prohresyvnykh metodiv plastychnoho deformuvannya. Monohrafiya [New technological processes using advanced methods of plastic deformation. Monograph]. V: UNIVERSUM-Vinnytsya [in Ukrainian].
[7]    Rosenberg, O. A, Trachenko, B. P. (1991). Formoobrazovaniya shlitsevikh otverstiy v trubnykh zagotovkakh metodom kholodnogo plasticheskogo deformirovaniya [Forming of spline holes in pipe blanks by cold plastic deformation]. Technology and organization of production, 2. 20–30  [in Ukrainian].
[8]    Ogorodnikov, V. A., Savchinsky, I. G., Nakhaichuk, O. V. (2004). Napryazhonno-deformirovannoye sostoyaniye pri formirovanii vnutrennego shlitsevogo profilya metodom obzhatiya na opravke [Stress-strain state during the formation of an internal spline profile by the method of compression on a mandrel]. Heavy engineering, 12. 31–33. [in Rassian].
[9]    Ohorodnikov, V. A., Nakhaychuk, O. V., Muzychuk, V. I. (2005). Prilozheniye teorii deformiruyemosti k resheniyu zadach mekhaniki formirovaniya vnutrennego shlitsevogo profilya obzhatiyem na opravke [Application of the theory of deformability to solving the problems of mechanics of forming an internal spline profile by compression on a mandrel]. Progressive technologies and equipment for forging and stamping production. Moscow: MSTU "MAMI". 66–75. [in Rassian].
[10]    Syvak, R. I. (2015). Plastychnistʹ metaliv pry nemonotonnomu navantazhenni [Plasticity of metals at nonmonotonic loading]. Tekhnika, enerhetyka, transport APC. Vinnytsya, 1(91). 108–111 [in Ukrainian].
[11]    Sivak, R. I. (2017). Evaluation of metal plasticity and research on the mechanics of pressure treatment processes under complex loading. Eastern-European journal of enterprise technologies, 6/7(90). 34–41. [in English].