编号 9 (171) (2025)

Pipeline system adapters are highly demanded parts in engine units. In pipeline systems operating in aggressive environments, these parts require the use of special non-ferrous alloys characterized by high strength. Their manufacture is very difficult. One of the options for their production is hot stamping of pipe elements under slow forming conditions. The article investigates the operation of forming an internal thickening on a thin-walled conical body blank. The purpose of forming the thickening is to prepare the end face of the adapter for pipeline systems, which is a truncated thin-walled one for further welding with other elements of pipeline systems. It is assumed that the formation of a thick edge is produced by partial upsetting of the end face of the blank. This operation was simulated in the DEFORM software package, during which an assessment was made of the effect of processing modes and the geometry of the working tool on the energy-power parameters of the process. It is assumed that the material of the blank is titanium alloy VT6. The material used assumes the implementation of the upsetting process in hot conditions under high-speed forming conditions, providing minimum forces and an optimal stress state of the workpiece. During upsetting, it is important to take into account the process parameters, such as pressure, temperature and speed, in order to minimize or avoid damage to the workpiece. A number of experiments were carried out, during which the influence of the cone angle, the working stroke of the tool, and the rate of deformation of contact friction were established. It was found that with the deformation scheme under consideration, the greatest influence is exerted by a change in the cone angle of the workpiece on the force, which is obviously associated with a change in the kinematics of the material flow at large cone angles.

The paper presents the results obtained in experimental studies of chip morphology and wear process that occur during milling of inconel 625 alloy obtained through additive technology Electron Beam Aadditive Manufacturing (EBAM). The sample was obtained from a wire in a pilot installation using proven technological modes. The microstructure and physical and mechanical characteristics of the inconel 625 sample were studied using certified analytical equipment. Carbide end mills were used as a cutting tool, machining was carried out with no coolant according to the counter milling operation across the synthesis direction in additive manufacturing. During the experiments, chipping was selected, which was examined after that using a scanning electron microscope (SEM) and X-ray diffraction analysis (XRD) equipment. Observation and analysis of chipping at various magnifications showed a change in its shape and an increase in the degree of yield strain depending on the intensification of cutting modes. A detailed study with the help of SEM for the cutting side of the facing showed that with increasing cutting modes, increased grain transfer of WC tool material to the facing surface is observed. This is an indicator of accelerated wear and premature failure of the cutting edges due to softening of the cobalt binding agent. Also, when studying cutting edges of the milling cutter using the XRD method, complex Cr23C6 carbide and NiW intermetallic compound were found. They contribute to increased wear on the milling cutter operating floors. The study of the wear characteristics of the operating floors of cutting tools and facing formed within machining operation allows making recommendations for improving wear resistance and determining rational operating modes.

The article discusses a hybrid technology that combines additive manufacturing of metal products using the WAAM technique and wave strain hardening aimed at improving the mechanical characteristics of the parts being created. WAAM technology is an additive manufacturing technique that through an electric arc melts metal wire, making three D metal products by layering. This technology combines the principles of traditional welding production and additive methods, making efficient parts production of complex shapes possible. Key advantages of WAAM technology are the following: speed of production, which reduces costs, as well as the ability to manufacture large and complex parts that are difficult or impossible to make using traditional techniques. However, when synthesizing products, the most popular problems are heterogeneity of microstructure, porosity and coarse- grain zones, which result in strength loss. To overcome these problems, it is recommended to use wave strain hardening, which provides a significant increase in the depth of hardening, creates compressive residual stresses and promotes fine grinding of the granular structure. A finite element model has been developed in ANSYS for the analysis of temperature fields and mechanical loads in a hybrid process. The simulation made it possible to optimize the modes of synthesis and wave strain hardening, taking into account thermal deformation effects. Experimental studies on the ES868 alloy have confirmed the effectiveness of the approach: the use of wave strain hardening resulted in structure refirenment (up to 10 times), hardness increase by 2,5 times, tensile strength by 1,5 times and yield strength by 2 times at one and the same toughness. The results prove the potential of hybrid WAAM technology and wave strain hardening for large-sized parts manufacturing with improved performance characteristics.

An adequate assessment of the contact interaction of rough surfaces at low nominal contact pressures (up to 2 MPa) is impossible without taking into account the microgeometry of the mating surfaces, and the complex pattern of formation of actual contact spots requires the use of simulated modeling of the contact interaction of real 3D maps of engineering surfaces or their models, which are fractal surfaces. The description of a fractal surface requires knowledge of the fractal dimension of the profile D (surface DS = D + 1) and the fractal roughness parameter G. These fractal parameters determine such structural features of the surface model as the radius of curvature of the upper part of the protrusion and the criterion for the transition from plastic deformation of the protrusion to elastic. The contact interaction of a fractal surface with a smooth, rigid, flat surface suggests that due to the presence of sub-roughness at the nanoscale, plastic deformation of the submicron surfaces occurs first, and then, as the normal load increases, an elastic contact spot forms. The article considers the case when the description of the surface model required the use of another parameter – the dimension DXY of the contact spots, which includes the number of irregularities in contact with an area greater than the selected one. The well–known fractal models of Majumdar-Bhushan (M-B) and others assume that the dimension of the surface and DXY numerically coincide with each other, which is not true. The article provides a comparison of the simulation results for cases when the fractal dimensions under consideration have different and identical values, and shows the magnitude of the error in estimating the load capacity of the contact of the conjugate surfaces.