Metalworking № 1 (133)/2023

Research of spectral composition of natural acoustic vibrations of ceramic-bonded grinding wheels

1. V. Ardashev, A. S. Zhukov

In work an experimental research of frequency spectrum of natural vibrations of ceramic-bonded grinding wheels (GW) is carried out. According to the known method of B. A. Glagovsky and I. B. Moskovenko the lowest frequencies of bending and plane natural vibrations of these circles are calculated. The initial data for calculations are physical and mechanical parameters of material andgeometric dimensions of circles, as well as the forms of natural vibrations. Then the results of empirical research and theoretical calculation are compared. The conclusion about the possibility of theoretical calculation of informative frequency, according to which it is advisable to monitor changes in the condition of a ceramic bonded ball bearing during its operation, is made.

Keywords: grinding process, ceramic-bonded grinding wheel, natural frequency, spectral composition, informative frequency range, acoustic analysis.

Milling of high-hard materials with ensuring the rational state of the technological cutting system. Part 1 и 2

1. Ya. Mokritskii, A. V. Kosminin, A. G. Serebrennikova, P. A. Sablin

The article presents the results of the study of the milling process of high–hard materials from the standpoint of the choice of conditions under which the minimum deviation of the technological cutting system „machine—tool—tool—part“ from its rational (equilibrium) state under different cutting conditions is achieved. It is established which parameters of acoustic emission are suitable for assessing its condition, it is shown how the parameters of the cutting mode affect the deviation of the technological cutting system „machine—device—tool—part“, it is shown what is the role of coatings on a metal-cutting tool.

Keywords: milling of solid materials, selection of cutting mode parameters and criteria for assessing the state of the technological cutting system.

Properties of the galvanothermal coating of the zinc—tin system on 30HGSA and 30HGSN2A steel. Hydrogen embrittlement and friction characteristics

1. I. Zakirova, A. A. Nikiforov, T. A. Bolsunovskaya, A. B. Laptev

The article considers the option of replacing the toxic cadmium coating with galvanothermal coatings (GTC) of the zinc-tin system. Comparative tests of the mechanical properties of 30HGSA, 30HGSN2A steels and the durability of 30HGSN2A steel with cadmium, zinc and GTC coatings were carried out. Tribological characteristics of 30HGSA steel with cadmium and GTC coatings are considered. And the tendency to overload protected steels 30HGSA and 30HGSN2A during application, coating formation and during accelerated tests in the salt mist chamber.

Keywords: steel 30HGSA, steel 30HGSN2A, GTC, cadmium coating, zinc coating, delayed brittle fracture, multi-cycle fatigue, hydrogen embrittlement, tribological characteristics, coefficient of friction, wear.

Technological assurance of the quality of operational surfaces of a workpiece made of austenitic steels

1. V. Maksarov, Van Dao Nguyen, A. E. Efimov, I. A. Brigadnov

Saint Petersburg Mining University, Saint Petersburg, Russia

An austenitic stainless steel with excellent physical and chemical properties is presented. The characteristics, methods of machining of austenitic steel with chip crushing are considered. A new method of mechanical processing of parts made of austenitic steel based on local cryogenic impact (LCI) and application in modern industry, especially in oil and gas production, are presented.

Keywords: austenitic steel, machining methods, chip segmentation and crushing, local cryogenic impact.

Features of magnetic abrasive t finishing of paired conical surfaces

In this article, the issue of the implementation of magnetic abrasive finishing in order to ensure the quality of conical surfaces of products is considered. The ring and cone of the synchronizer are selected as products having conical surfaces, which are subject to intense abrasive wear during operation. The necessity of observing the parallelism of the working surface of the pole tip to the surface to be processed, as well as the need to ensure a uniform working gap along the entire profile of the conical surface to be processed, is substantiated. As a result of computer modeling and a series of experimental studies, taking into account the parallelism of the working surface of the pole tip and the treated surface, the distribution of magnetic induction in the working gap is obtained. The samples processed according to the proposed method have the best surface quality in terms of roughness.

Keywords: magnetic abrasive finishing; conical surface; finishing treatment of alloy steel.

Application of game theory methods for decision-making at digital transformation projects selection

1. V. Surina, V. B. Mironenkov

The article discusses models of game theory for decision-making in conditions of uncertainty, explains the relevance of the application of game theory in conditions of rapidly changing external factors, formulates the purpose of the study, forms a decision-making method of selection projects using game theory, forms criteria for evaluating projects/project complexes. The relevance of the work is due to the active growth of interest in game theory as a method of decision-making in conditions of risk and uncertainty. The priority task is to make the most accurate, quick decisions that ensure the flexibility and sustainability of the business.

Keywords: digital transformation, business transformation, game theory, decision making, project management, uncertainty conditions, innovation management, projects selection.