Видання НТУ "ХПІ"
Постійне посилання на розділhttps://repository.kpi.kharkov.ua/handle/KhPI-Press/62886
Переглянути
3 результатів
Результати пошуку
Документ Actual contact area on the worn clearance face of the cutter with the round kyborite insert(Національний технічний університет "Харківський політехнічний інститут", 2023) Manovytsky, Olersandr; Klymenko, Sergii; Klymenko, Serhii; Kopeikina, MarynaFor a tool equipped with a circular cutting insert, a dependence is proposed for calculating the nominal area of the contact area on the back surface. It is proved that the actual area of the contact area of the tool differs significantly from the nominal one due to the presence of a system of micro-irregularities, which makes a difference in the assessment of machining process parameters. Using the example of a tool equipped with a circular cutting insert made of polycrystalline cubic boron nitride ciborite, an approach to determining the actual contact area of the back surface with the workpiece during finishing turning of hardened steel is considered. The possibility of taking into account the influence of the system of irregularities in the contact area, determined by the parameters of its topography, on the size of the actual area is shown, and the ratio of the actual and nominal areas of the contact areas of the tool is determined, and it is found that, depending on the degree of development of the microrelief, the ratio of the actual and nominal areas of the contact surface of the cutter differs by at least 20%. It is shown that the actual contact area is also related to the total length of the main and auxiliary cutting edges, determined by the maximum values of the main and auxiliary angles in the cutter plan, and the size of the wear chamfer on the back surface of the cutter.Документ Calculation of shear angle when cutting with a tool of a negative rake angle(Національний технічний університет "Харківський політехнічний інститут", 2022) Manovytskyi, O.; Klymenko, S.; Burykin, V.The article considers the results of the study of the cutting process in order to obtain the calculated dependences of the shear angle oF the physical and mechanical properties of hard-worked iron-carbon steels and alloys in thermobaric conditions of the cutting process and the value of the negative rake angle which is a typical tool for processing with polycrystalline superhard materials (PSHM) cutting tools. When cutting, the formation of chips occurs in the plastic flow of metal in the area of cutting or fracture with the formation and subsequent development of cracks and the subsequent separation of elemental or stepped chips. A well-known chip shaping scheme with one plane shift and the value of the contact area of the front surfaces of the cutting elements with the allowable material to be removed are used to describe the contact phenomena in the chip forming zone and calculate the shear angle in this plane. It is established that the inverse relationship between the shear angle and the negative rake angle of the cutting element indicates that the increase in the negative value of the rake angle leads to a decrease in the shear angle. The specific elongation and shortening of the processed material at the cutting temperature are defined by the authors as the characteristics of shear plasticity and selected for use in the calculation of the values of shear angles during blade processing. As a result of this work, the calculated dependences of the shear angle values on the physical and mechanical properties of heavy duty ferro-carbon steels and alloys in thermobaric conditions of the cutting process and the value of the negative rake angle, which is characteristic of machining with tools of PSHM equipped.Документ Structure, composition and mechanical properties of multi-layer vacuum-arc nitride coatings(Національний технічний університет "Харківський політехнічний інститут", 2022) Klymenko, S.; Klymenko, S. An.; Manokhin, А.; Stolbovoy, V.; Beresnev, V.; Šiška, F.; Chlup, Z.The conditions of application of multilayer vacuum-arc nitride coatings on a substrate made from polycrystalline cubic boron nitride (PCBN) are considered using the samples of (TiAlCrY)N/ZrN, (TiZr/TiSi)N, (TiAlSiY)N/CrN compositions. A schematic diagram of a vacuum-arc installation for applying similar coatings is presented, and the technological conditions of coating formation are considered. The structure and composition of the coatings were studied during diffractometric studies, and the performance of coated tools was examined when turning hardened steel. A large amount of the droplet phase in the (TiAlCrY)N/ZrN coating was established. The lattice parameters of two nitrides with an fcc crystal lattice were determined: ZrN – 4.590 Å, TiAlCrYN – 4.203 Å. CSR (coherent scattering region) of the ZrN phase is 5.4 nm at the microstrain level ε = 4.79·10¯³. High homogeneity and low defects in the thickness of the (TiZr)N/(TiSi)N coating were established – the amount of droplet phase is insignificant. The CSR of the coating is 24.2 nm at the level of microstrain ε = 5.76·10¯³, and the predominant texture orientation is (111). A small amount of the droplet phase was found in the (TiAlCrY)N/CrN coating. Both coating layers are characterized by the formation of phases with a cubic (fcc) crystal lattice, and a strong (111) texture occurs. The crystallographic planes (111) of the phase grains are mainly oriented parallel to the coating interface. The size of the CSR is 14.6 nm. It is shown that multilayer vacuum-arc coatings lead to an increase in the tool life of PCBN cutting tools by reducing the effect of adhesive sticking of the processed material and reducing the intensity of chemical interaction in the cutting zone.