Materials Science Forum Vol. 1037

Abstract: Products with varying cross-sectional height are used in various hydraulic pipelines [1-4]. These products are very easy to manufacture. However, when it comes to hydraulic pipelines of fuel systems, it is essential to use materials resistant to aggressive effects, which are rather difficult to handle [5-8]. In this case, one of the possible options for obtaining such products is hot forming, namely crimping. In view of this, the article considers the crimping of shells made of titanium 6Al-4V alloy. Various combinations of technological parameters and their influence on the flow of metal and the geometry of products are considered. Rational deformation-rate conditions of deformation are found.

Abstract: To predict the parameters of the quality of the processed parts and the period of durability of the cutting tool, mathematical models are needed that will allow us to calculate not only the mathematical expectation of the parameters of the machining process, but also the dispersion of these parameters. The working capacity of the tool and the quality parameters of the parts depend significantly on the temperature on the contact surfaces of the tool, as well as on the surface of the workpiece. Mathematical dependences for calculating the components of the total heat generation capacity during turning are given. It is assumed that the yield stress, which determines the cutting and friction forces on the contact surfaces of the cutter, workpiece and chip, depends on the temperature in the area of plastic deformation. The heat transfer at the boundaries of objects in contact with the process fluid or air is given in the form of the Newton-Richman law. The equations of thermal conductivity of contacting objects were solved together with the general boundary conditions in the contact zone, using the finite element method. The results of numerical simulation of the main component of the cutting force and temperatures in the contact zones of the face of the cutter with the chips and the fiank surface with the workpiece, depending on the yield strength of the workpiece material, are presented. The values of fluctuations in the cutting force and contact temperatures depending on the spread of the yield stress of the workpiece material during turning of workpieces made of 45 and 12X18H10T steels are determined. Based on the results of numerical modeling, regression equations are obtained for calculating the tangential component of the cutting force, the temperatures on the face and flank surfaces of the cutter, and the temperature on the surface of the workpiece.

Abstract: The purpose of this work is to increase the productivity and accuracy of processing long-length parts of the "shaft" type on CNC machines. Based on the analysis of existing methods for improving the accuracy of processing long shafts on CNC machines, a new method for controlling the spatial error of processing long shafts by changing the processing modes was proposed. The proposed method allows, by changing the processing modes, namely feed, to reduce the radial component of the cutting force and reduce the amount of deflection when machining parts on CNC machines. A technical and economic analysis and justification of scientific research was carried out. The economic effect of the proposed method.

Abstract: In this work, the experimental research was carried out on the processing of the cutting surface of a grinding wheel with a ceramic bond via continuous laser radiation with a wavelength of 10.6 μm. The influence of laser radiation power, processing speed on the depth and width of the obtained cut was investigated. A full factorial experiment was carried out with varying factors at two levels. In the form of a regression equation, a mathematical model of the effect of radiation power and processing speed on the output parameters of the process is obtained. Using Fisher's criterion, it is shown that the resulting equation adequately describes the process under the study. The analysis of the regression equation makes it possible to assess the relative influence of each factor and the effects of the interaction of factors on the depth and width of the cut on the surfaces of the grinding wheel.

Abstract: It is noted that the technology for the manufacture of ferrosilicon-magnesium modifiers (crystallization into an ingot in a mold or into a chip on a water-cooled drum) forms their quantitative and qualitative structural differences: the size and distribution of phases, the scatter of the content of elements, etc. The fundamental differences are shown and the features of the distribution of silicon as a base element in ingot and chip modifiers are described. It was found that in ingot modifiers the vast majority of silicon-containing phases are ξ(FeSi) and ζ' (FeSi₂), and with a significantly lower content of pure silicon particles and phases, these are α₁(Fe₃Si) and α₂(Fe₂Si). The picture of the phase structure of the modifier chip has been determined. In it, the 1st mode corresponds to the presence of a set of phases α₁(Fe3Si) and α₂(Fe2Si), and the 2nd mode, as well as in the ingot modifiers ξ (FeSi) and ζ'(FeSi2), but is shifted to the lower boundary of the region their existence. Particles of pure silicon are completely absent in the chip modifier.

Abstract: The development and introduction of new nickel-based heat-resistant alloys with a special combination of an increased complex of physicomechanical properties is a priority task for modern materials science.

Abstract: Investigations of the effect of hardening heat treatment modes on the properties of specimens from the CuNi3Si alloy were carried out. The modes of hardening and temperature-time parameters of aging, which increase the operational characteristics of structural elements from the CuNi3Si alloy, have been determined. Investigations of the microstructure of the obtained samples and energy-dispersive X-ray microanalysis of the hardening phase have been carried out. The sensitivity of the hardness of the samples to the density and size of finely dispersed particles released during aging, recognized as nickel silicide Ni₂Si, was revealed.

Abstract: A method for determining temperature stresses in a welded joint of a thin-walled pipe with a base is described. The method is based on experimental data of temperature measurement at reference points of the structure. The features of the elements of the welded joint made of carbon and high-alloy structural steels and the modes of electric arc welding were taken into account. The efficiency of using spline approximation of experimental data to obtain analytical dependences of the distribution of temperature fields and stresses, as well as to obtain a solution of the heat equation by numerical differentiation and integration for this case, is shown. Formulas for calculating temperature stresses for the case of an asymmetric temperature distribution in a cylinder under the action of a moving high-intensity heat source are obtained.

Abstract: A model of the magnitude of the stresses of the tip of the cutting blades of a thread-forming tool based on the theory of a homogeneous body is proposed. A model of second-order materials is considered. A description of the stress state is given using two stress tensors independent of each other.

Abstract: The article discusses the effect of epilamated coatings during mandrelling. The picture of the change in contact stresses in the DEFORM-3D system is presented. It was established that a decrease in the coefficient of friction from 0.9 to 0.6 leads to a decrease in the number of foci and areas of contact stresses, as well as temperature analysis showed that a decrease in the friction forces reduces heat transfer in the cutting zone by about 40 ° C.