Key Engineering Materials Vol. 910

Abstract: The article describes the orthogonal turn-milling technology applied for powder high speed steels. The cutter with carbide inserts was used in the experiments. The orthogonal turn-milling model was developed to improve the surface quality by choosing optimal cutting modes based on the simulation results. The mathematical model makes it possible to predict geometric surface deviations. The impact of cutting speed, tool feed and radial depth of cut on the geometric surface parameters was identified. The results make it possible to achieve the satisfactory level of surface quality without deteriorating the machining productivity. The avenues for further research are outlined.

Abstract: The flat grinding of low-rigidity prismatic workpieces side surfaces is investigated. Algorithm of determination of optimal conditions for low-rigidity prismatic workpieces flat grinding has been developed. The optimization of parameters in the range of allowable values is carried out with the view of ensuring the maximum process efficiency. Mathematical models for determination of maximum elastic deformation of prismatic workpieces when fixing and machining are presented.

Abstract: The authors of the article analyzed the properties of the fluidized bed during the formation of the abrasive-polymer compound for waterjet cutting. It is noted that in the process of applying the polymer shell to the surface of the abrasive grain in the fluidized bed, the effect of slippage and the absence of the influence of the installation wall on the value of the longitudinal velocity of particles near it is observed, which allows to increase the productivity of creating an abrasive-polymer compound.

Abstract: The analysis of existing processing methods was carried out. A series of virtual experiments was performed; based on their results dependences of the height of residual ridges, the temperature on the workpiece surface and the temperature in the cutting zone on the parameters of the processing mode when boring internal holes with a rotating cutter block were constructed based on the results of virtual computer simulation. An optimization model of the boring process was built. The objective function was received. Within the optimization model framework, solutions were obtained that allow, at the highest value of axial feed, to ensure the required surface quality and avoid changes in the physical and mechanical properties of the material.

Abstract: The article shows the relevance and scientific significance in the use of a combined processing method that combines the cutting process and surface plastic deformation, which provides an increase in the efficiency of processing of the basic flat end surfaces of electrical parts made of copper, the study of the patterns of microrelief formation during mechanical processing and plastic deformation of a copper surface. It was found that the use of a combined tool allows you to combine several transitions, which provides an increase in processing productivity by reducing the machine and auxiliary processing time. Replacing the grinding operation of the existing technological process with diamond burnishing can significantly improve the quality of the processed surface.

Abstract: The article discusses the issues of increasing the efficiency of using nanocoatings of the working surfaces of a tool operating at relatively low cutting speeds. A theoretical and experimental approach is proposed, which is based on a model of the interaction of the internal three-dimensional state of the epilame layer, a two-dimensional material film and the material line closing it. An analysis of the state and shape of a liquid layer on a flat surface is given under the assumption that Young's equation is valid, which connects the contact angle with the values of surface stresses. Dependencies and a technique are given that allow you to control the behavior of an epilame drop on the surface of the cutting element. It was found that when thin-film coatings are applied from epilame solutions, a film is created on the surface of the instrument, which significantly changes the energy properties of the surface. It is shown that during the study of oil absorption of epilamated and unepilamated surfaces, as well as the study of the behavior of oil, the greatest retention of oil is observed during intermittent epilamated, presented in the form of large drops, the area of which depends on the area of unepilamated areas. It is recommended to carry out the following experimental research technique, which is associated with obtaining the initial parameters for determining the geometric parameters of a drop of the material under study on a flat surface. The radius of the projection of the drop onto the substrate, the profile of the drop when scanning the side view and then taking into account that the drop is a figure of rotation are determined, taking into account the previous data, its volume, the value of the wetting angle and the height of the drop are determined.

Abstract: The influence of various design and technological parameters of the process of plasma deposition of coatings on their quality is considered. In the process of research, regularities were revealed and relationships were established between the factors and criteria of technological processes, which make it possible to solve optimization problems when developing technological recommendations and improving the methods of applying plasma coatings. The results of the research are the obtained mathematical models that can be applied to analyze the influence of individual factors, as well as their combination on the quality indicators of the process of forming coatings with given physical and mechanical properties.

Abstract: This paper presents studies of welded joints of steels 30KhGSA and 40KhMFA made by rotary friction welding. The influence of the forging force on the microstructure and tensile properties of standard specimens and specimens with a notch in the contact zone is analyzed. The results of measuring the microhardness and fractogram of the fracture surface are presented. It has been established that in the selected range of forging forces, the strength of the contact zone is higher than other sections of the thermomechanical affected zone and the base metal of the materials to be welded. In this case, the maximum strength of the contact zone occurs at lower values ​​of the forging force due to the formation of common grains along the contact line as a result of the process of mutual volumetric recrystallization.

Abstract: The choice of cutting mode elements in end milling has a significant effect on machining performance. However, an increase in these parameters leads to an increase in cutting force and vibration amplitude. Therefore, the designation of the elements of the cutting mode must be carried out taking into account the dynamic phenomena accompanying milling. The article shows the influence of the depth of cut on the amplitudes of forced vibrations. The choice of the optimal values of the cutting mode during end milling is proposed to ensure the minimum vibration amplitude.

Abstract: To improve the quality of human life, sometimes, surgical interventions are required to replace or retain damaged tissue during reparative regeneration. Titanium and titanium alloys are well-proven biocompatible materials. The methods of modeling the phase composition of the titanium alloy can be used to predict the chemical and physical-mechanical properties of implants and suture material. In this research, the features of the titanium drawing process are investigated, recommendations are given for thermo-mechanical processing and the choice of a lubricant. Modeling the structure and phase composition of alloys allows predicting their properties and choosing the optimal technological parameters for all drawing transitions. Drawing must be performed in a friction mode close to the hydrodynamic regime with intermediate annealing to control the phase composition of titanium, restore the plasticity resource, and heal crystal structure defects. The composition of atmospheric gases during annealing makes it possible to control the phase composition and properties of the alloy. The use of exfoliated graphite is proposed as a lubricant applied to the anodized titanium surface.