МИКРОСТРУКТУРНЫЕ ИЗМЕНЕНИЯ В СТАЛИ 45, ВЫЗВАННЫЕ ВОЛНОВЫМ ДЕФОРМАЦИОННЫМ УПРОЧНЕНИЕМВ результате микроструктурных исследований образцов из стали 45 установлено, что с увеличени-ем равномерности волнового деформационного упрочнения в поверхностном слое протекает ряд процессов. При небольшой равномерности упроч-нения формируется развернутая на угол 45° волок-нистая структура и глобулярный феррит. При воз-растании равномерности упрочнения сначала про-исходит выстраивание перпендикулярно деформи-рующему усилию зоны полного диспергирования феррита и перлита, а затем образование высоко-дисперсных зон в форме линз -переупрочненных областей.Ключевые слова: микроструктура, упрочне-ние, волна деформации, феррит, перлит, равномер-ность, гетерогенность, глобулярность.A.V. Kirichek, S.V. Barinov, S.V. Davydov, A.V. Yashin, A.A. Zaitsev, A.M. Konstantinov MICRO-STRUCTURAL CHANGES IN STEEL 45 CAUSED BY WAVE STRAIN STRENGTHENINGThe application of surface plastic deformation (SPD) for the formation of a heterogeneous structure became possible with the advent of wave strain strengthening (WSS). In contrast to well-known SPD methods this method allows ensuring a required law of the distribution of solid and viscous areas at a large depth and ensures the absence of a sharp boundary between the areas with different hardness and viscosity which excludes stress concentration and does not cause micro-cracks nucleation. Earlier, with the aid of WSS one managed to increase a resistance to a contact crumbling by a factor of three -five times, and a breaking pointup to 8% on flat samples of steel 45. In the work there were carried out investigations of micro-structural changes occurred at different uniformities of the wave strain strengthening on flat samples of steel 45. As a result of investigations it was established that in a surface layer from the side of a deformation source with the increase of strengthening uniformity (from K = 0.2 up to K = 0.8), because of the increase of deformation impact density per unit area of a surface the thickness decrease of the visible grain deformation area takes place. The thickness increase of visible grain deformation area on the opposite (back) side begins with the value of K = 0.6 and higher. At WSS with surpassing K=0.2; 0.4, on the back side at K=0.8 there is arisen a formation of fibrous textured structure in which grains are unfolded to the angle of 38-41º. At the wave strain strengthening with K=0.4 there is determined a formation of globular ferrite in a surface layer.Key words: micro-structure, strengthening, deformation wave, ferrite, pearlite, uniformity, heterogeneity, globularity. ВведениеДостаточно большой интерес для со-временной промышленности представляют гетерогенные материалы, например соче-тающие высокие параметры ударной вяз-кости и твердости. Материалы с гетеро-генной структурой, в отличие от компози-ционных материалов, имеют однородный химический состав, а гетерогенные свой-ства задаются в гомогенном материале технологически, например термообработ-кой (ТО) или химико-термическ...
ПОВЫШЕНИЕ ПРОЧНОСТИ СТАЛЕЙ 45, 40Х И 35ХГСА УПРОЧНЕНИЕМ ВОЛНОЙ ДЕФОРМАЦИИПредставлены данные о влиянии упрочнения волной деформации на прочность сталей 45, 40Х и 35 ХГСА. Для повышения прочности данных ста-лей предлагается в их поверхностном слое волной деформации создавать структурированные гетеро-генно упрочненные области, состоящие из чере-дующихся твердых и вязкопластичных участков.Ключевые слова: волна деформации, твер-дость, гетерогенно упрочненная структура, проч-ность.A.V. Kirichek, S.V. Barinov, A.V. Yashin STRENGTH INCREASE IN STEEL 45, 40H AND 35HGSA BY DEFORMATION WAVE STRENGTHENINGStrength increase by a deformation wave is more advantageous in comparison with other ways of strengthening as it allows ensuring in a surface layer a larger depth of strengthening with a smooth transition from a strengthened surface to an non-strengthened one which is especially significant for materials operating under conditions of static loading. The paper reports the fulfilled investigations of the impact of strengthening heterogeneity with a deformation wave upon strength of steel 45, 40H, 35HGSA. The investigations of strength properties were carried out both on samples strengthened only on one side (on contact one), and on samples strengthened on two sides (on contact and supporting ones). As a result of investigations it is defined that at one-sided treatment of steel 45 with strengthening uniformity increase a strength limit increased by 8%, the ductility decreased by 37%, an elastic limit increased by 43%. The strengthening uniformity increase in steel 40H resulted in strength limit increase by 13%, elasticity decrease by 38% and elasticity limit increase by 81%. At steel 35HGSA strengthening with uniformity increase there was observed a strength limit increase by 4.2%, plasticity decrease by 28% and elasticity limit increase by 51%. In case of two-sided strengthening with a deformation wave the values of strength properties of steel 40H did not actually change in comparison with one-sided treatment. The two-sided strengthening of samples made of steel 35HGSA brought to the growth of their strength limit by 2.8% and ductility limit by 20% as compared with one-sided treatment.
The investigations carried out deal with the re-gularity study in the distribution of shock pulse energy at multiple procedures of loading. The experimental researches were carried out on the specially developed test bench in which under all waveguides (or tools) of the shock system there were situated independently (separately) sensors connected with an oscilloscope registering parameters of a shock pulse (a form, amplitude, duration). As a result it was determined that the increase of the eccentricity in the symmetry axis location of a head and a waveguide (or a tool) and their number in the shock system contributes to the reduction of an energy portion sent to the deformation source. The application of multi-contact schemes of loading allows sending large total energy of a shock pulse to the deformation source to accept conditions of experiment fulfillment. At that the energy portion of a shock pulse fall-ing to each waveguide (or a tool) in the multicontact scheme as compared with the singlecontact one decreases (for rod-formed waveguides by 20%, and for spherical tools – by 15%) at the installation of each subsequent waveguide (or a tool) in the shock system.
Представлены данные о влиянии числа, гео-метрии, расположения инструментов в многокон-тактной ударной системе на распределение микро-твердости в поверхностном слое. Эксперименталь-но установлена возможность многоконтактных ударных систем передавать в очаг деформации большую суммарную энергию ударного импульса. Показано, что производительность многоконтакт-ных ударных систем может быть повышена на 50%, без ухудшения параметров упрочнения, за счет увеличения расстояния между инструментами с плоским типом торца.Ключевые слова: ударный импульс, упроч-нение, волна деформации, микротвердость, волно-вод, боек, ударная система.
The article discusses ways to solve the problem of wear of the rotor bearings of turbine units at the moments of start–up and shutdown. The concept of a new type of elastic–damping combined sliding bearings, which combines the use of ferromagnetic fluids in the design of multi–blade bearings, is proposed. On the basis of this, a design of a petal bearing with an electromagnetic effect on elastic elements and a ferromagnetic lubricant has been proposed. The properties and features of the use of ferromagnetic fluids in precision engineering as a lubricant are described. A mathematical model of an electromagnetic petal bearing with a ferromagnetic fluid is proposed on the basis of the Reynolds equation from the course of magnetohydrodynamics, Maxwell's equations for a magnetic field, a system of equations in displacements based on the theory of cylindrical shells. An algorithm for the operation of the rotor support during start–up, shutdown, as well as when the power supply of the electromagnets is turned off.
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