Metalworking № 5 (137)/2023

Material cutting

Kizhnyaev Yu. I., Nemtsev B. A., Petrov V. M. Technology for repairing pipes of gas-dynamic propelling installations

The content of operations to remove a defective layer on the surface of a deep hole with an initial diameter do = 13,7H7 (Ra = 0,2 μm) is considered in order to restore the accuracy and quali-ty of the pipe with an increased hole diameter. The results of processing holes in a batch of pipes are given.

Keywords: deep precise hole, defective layer removal, technology of finishing and coating processing.

Mokritskii B. Ya., Kosminin A. V. Principles and innovative technologies for increasing the durability period of metal-cutting tools in the processing of hard-to-process stainless steel 09Х17Н7Ю

The costs of designing metal-cutting tools for the manufacture of parts made of hard-to-process materials are steadily increasing due to the growing demand for hard-to-process materials. Accordingly, the costs of the tool are also growing. Measures are needed to reduce these costs. The simplest measure is the development of coatings for carbide tools. The results of the development of new rational coatings are proposed. The purpose of the study: to increase the period of resistance of turning tools during external turning of hard-to-process corrosion-resistant stainless steel grade 09Х17Н7Ю due to the use of new coatings applied by condensation with ion bombardment (CIB method) on a hard alloy grade ВK8. The task to which the article is devoted is to increase the durability period of standard replaceable carbide plates of turning cutters during external turning of hard-to-process specialized stainless steel grade 09Х17Н7Ю . The novelty of the work consists in the development of the basic principles of innovative technology for increasing the durability period of metal-cutting tools when processing hard-to-process stainless steel 09Х17Н7Ю.

Keywords: the choice of rational coatings, increasing the durability period of cutters, turning of hard-to-work steel.

New materials and technology

Keksin A. I., Filipenko I. A., Sorokopud N. I., Lutov D. A. Formation of the quality of flat surfaces made of aluminum alloy of the amc brand by means of magnetic-abrasive finishing

The present article solves the actual scientific and technical problem of forming the quality of flat surfaces made of aluminum alloy of the AMc brand by magnetic abrasive treatment. The research was carried out on the basis of an experimental complex for magnetic abrasive processing. On the basis of the experimental data obtained, a physical and statistical model and graphical dependences of the influence of magnetic abrasive treatment factors on the quality (roughness according to the Ra parameter) of flat surfaces made of aluminum alloy of the AMc brand were constructed. For the practical use of the method of magnetic abrasive treatment as the final finishing operation in the manufacture of surfaces of parts of electrical products made of aluminum alloy of the AMc brand, the most rational and optimal conditions for magnetic abrasive treatment have been determined.

Keywords: aluminum alloy AMc, surface roughness, magnetic abrasive finishing, abrasive finishing in a magnetic field, finishing of flat surfaces.

Kilmetovа L. R., Khadiullin S. Kh., Astanin V. V., Dubin A. I. Methods for determining surface residual stress in parts made of heat-resistant materials

In this article, the formation of surface residual stresses arising as a result of mechanical processing of a nickel-based superalloy is studied by numerical simulation and experimentally. One of the important tasks in the production process of mechanical engineering products is to ensure not only the required shape and size, but also the optimal condition of the material. To ensure high quality of engineering products, it is necessary to have a complete understanding of the process of occurrence and distribution of residual stresses during turning. This requires the development of effective methods and approaches for their determination and control. Methods for measuring and non-destructive testing of residual stresses are also analyzed in this paper. The research results can be useful for increasing the service life of parts made of heat-resistant alloys.

Keywords: residual stresses, measurement, control, cutting tool, machining.

Dudkina N. G., Zakharov I. N., Kharlamov V. O., Barinov V. V. Investigation of the microstructure and properties of the surface layer of medium-carbon steels subjected to combined treatment EMT + SPD

The results of studies of the structure and microhardness of the surface layer of medium-carbon steels 40Х, 55, 60С2А, subjected to combined hardening by electromechanical treatment followed by surface plastic deformation (EMT+SPD), are presented. The influence of the chemical composition of the steels under study on the structural-phase state of the strengthened surface layer (white layer) was studied using light and electron microscopy methods. The characteristic features of microhardness distribution in surface-hardened layers of steels of different chemical compositions are considered. The research results can be used to further develop ideas about the nature of white layers and expand theoretical concepts in the field of combined EMT+SPD surface hardening technology.

Key words: steel, combined hardening, electromechanical processing, surface plastic deformation, structure, white layer, microhardness.

Golovkin P. A., Dvoretskov R. M. On the methodology for detecting sulfur impurity content critical for the manufacture of electric vacuum devices in oxygen-free copper rods

Taking into account the possibilities and peculiarities of various methods of analysis of the chemical composition of metallic materials, the difficulties in determining the actual local content of sulfur impurities in rods of oxygen-free copper grade “M0b” are considered. It is shown, in particular, that the technique of quantitative determination of sulfur prescribed by the Russian State Standard 10988 with sampling according to the Russian State Standard “GOST 24231” does not provide accuracy required for safe use of material in parts of working area of electric-vacuum devices. On the basis of comparison of possibilities and features of modern and classical methods of checking the chemical composition of metallic materials for quantitative content of various impurities, it is also shown that none of the current standard methods does not provide guaranteed detection of sulphur impurities in bars of oxygen-free copper. According to the results of the conducted research, a composite method of determination of local sulphur content in the material is proposed to exclude the loss of vacuum density and sublimation of sulphur impurities into the working zone of electrovacuum devices.

Key words: oxygen-free copper, rods, parts, electrovacuum devices, working area, vacuum depth, temperature, impurities, sulfur, chemical analysis, peculiarities of methods, distributed and local impurity content.

Design of technological systems

Maslenikov I. A., Sokolov Yu. А., Sokolov V. Yu. Process of chip forming’s modelling

The article discusses the modeling of the chip formation process when cutting metals with a blade tool. The dependence of the chip type on the parameters of the cutting process is determined. To implement mathematical models, the basic principles of the theory of metal cutting, methods of similarity theory and numerical methods are used.

Keywords: cutting of materials, technologies, modeling, chip forming.