№ 7 (2024)
- Жылы: 2024
- Мақалалар: 5
- URL: https://journals.rcsi.science/2223-4608/issue/view/18325
Бүкіл шығарылым
Materials science in mechanical engineering
GAS-CYCLING PROCESSES OF CHEMICAL AND THERMAL TREATMENT: REGULATION OF THE NITRIDE LAYER STRUCTURE FOR IRON AND STEEL
Аннотация
The relevance of the research is determined by the needs of mechanical engineering in the development of inexpensive and effective technologies for surface hardening of steel products, which include gas nitride hardening. The aim of the work is to study the effect of nitride hardening in the gas-cyclic regime on the kinetics of growth of diffuse layers and their phase composition in case of iron and steel: ChWMn tool steel and corrosion-resistant maraging steel 03Ch11Ni10Mo2Ti (WSTST17). In addition to isothermal processes (at 520 ℃ and 620 ℃), processes with temperature changes at active and passive stages (thermal cycling 520 ℃ / 620 ℃) have been studied. It has been found that gas and thermal cycling significantly increases the thickness of the diffusion layer in iron compared to traditional nitride hardening in ammonia, and this is mainly due to the growth of the internal nitriding zone. Processes with multitime repeat short half-cycles, which end in an active saturation stage in ammonia and contribute to the formation of a developed nitride zone. The formation of surface layers in iron without an ε -phase occurs in two-stage processes with a final passive stage. It is shown that thermo-gas cyclic processes provide a multiple increase in the thickness of the internal nitriding zone in ChWMn steel. Processes with a duration of half cycles of 1 and 1,5 hours with the final stage of denitration contribute to the predominance of the γ' phase in the carbonitride zone, which explains the increase in wear resistance. A thermal gascyclic process of 530 ℃ / 580 ℃ in a pulsating ammonia-air mixture with a final passive stage is used to form a junction zone based on the γ'- phase in steel 03Ch11Ni10Mo2Ti (WSTST17).
Science intensive technologies in mechanical engineering. 2024;(7):3-14
3-14
Technologies of mechanical processing of workpieces
CUTTING ABILITY FEATURES FOR NEW HIGH-STRENGTH TITANIUM ALLOYS WITH AN ULTRAFINE-GRAINED STRUCTURE USED FOR AIRCRAFT PARTS
Аннотация
The results of experimental studies of the cutting parameters effect (cutting speed, feed, depth-of-cut) on the roughness of Ra, the microstructure of the surface layer of Ti-6Al-4V alloy samples with a conventional coarse-grained (CG) and ultrafine-grained (UFG) structure obtained by equal-channel angular pressing are presented. In framework of solving the problem connected with studying the machinability of a new VT6 alloy having an UFG structure, the development of a methodology for experimental research under turning was carried out. Physical parameters such as vibrations and noise under cutting, power consumption, numerical parameters of roughness, the magnitude and the pattern of residual stresses distribution and others are determined according to cutting modes and the tool used for the operation. It is shown that when turning at a low cutting speed, the roughness of CG sample is better than UFG of the alloy. With an increase in the cutting speed by 1,5 times, on the contrary, a sample with an UFG structure has a lower roughness Ra compared to a CG sample. Differences in the morphology and microstructure of the chips formed within comparative machining are discussed, taking into account types of microstructure of the alloy being treated, namely, presence of plastic flow lines in the chip microstructure after turning an UFG sample, the formation of large shifts, chips and tiny fractures in the chips after turning a CG alloy. It is found that new titanium alloys under turning obtain better cutting machinability in terms of such parameters as surface roughness, noise and vibration under cutting, and a more favorable character of residual stresses and riveting in the surface layer. Studying these factors, it is possible to predict a significant reduction of tool wear and stabilization of its durability compared to conventional coarse-grained titanium treatment.
Science intensive technologies in mechanical engineering. 2024;(7):15-23
15-23
Technological processes automated control
AUTOMATED TECHNOLOGICAL SUPPORT AND IMPROVEMENT OF THE OPERATIONAL PROPERTIES OF MACHINE PARTS
Аннотация
The article outlines two directions of automated engineering support for the operational properties of machine parts (wear resistance, contact stiffness, etc.). The first direction is a traditional one. It's a two-stage provision of the operational properties of machine parts: in the first stage it is the dimensioning of working surfaces quality of the part that determines the required values of operational properties; in the second stage it is technological provision of quality parameters for the working surfaces of machine parts. The second new direction is a single – stage automated engineering support for the current operational properties of machine parts, which has been actively developed over the past 25 years at the Bryansk State Technical University. It is based on the theoretical and experimental dependences of the relationship between the operational properties of machine parts directly with the processing modes of their working surfaces. Various automated systems of scientific research have been developed to obtain experimental dependencies. An example of such an automated system for studying contact stiffness is given. Adaptive control systems used on various machines for high-performance engineering support aimed at obtaining the required quality parameters of the treated surfaces and their operational properties have been developed. When processing new materials and taking into account the absence of theoretical and experimental data, it is possible to use self-learning technological systems. An example of such a system used for a lathe, is given. All these developments contribute to the creation of the machines with artificial intelligence.
Science intensive technologies in mechanical engineering. 2024;(7):24-33
24-33
CREATION AND DEVELOPMENT OF HIGHLY RELIABLE INFORMATION AND CONTROL SYSTEMS WITH ELEMENTS OF ARTIFICIAL INTELLIGENCE FOR ADVANCED TECHNOLOGICAL COMPLEXES
Аннотация
Methods and means of improving complex technological equipment are shown through the operational assessment of the quality of implemented technologies realtime. This is proved by the fact that implementing technological operations on universal equipment each time requires modeling dynamic processes and taking into account a large number of uncertainty factors that affect the geometry generation quality. It is not possible to be a priori aware of these factors. There is a need to create new information technologies with the possibilities of universal application for immediate understanding of various dynamic processes in diagnostic, identification and control systems. Standard computer systems for statistical analysis and optimization of dynamic processes with the possibilities of universal application for various implementations of modern technologies have been introduced. The possibility of using integrative criteria and methods of artificial intelligence for diagnostic systems, identification and control of advanced technological complexes is shown. The implementation of information systems for the management of complex objects of various technological purposes is presented. The proposed modeling methods and approaches have been tested at various machine-building enterprises when processing parts on turning, milling and grinding machines, both universal and CNC. The research results made it possible to implement new principles of automated control and optimal adjustment of technological processes in real time and create an automated system for evaluating their quality, which allows increasing the efficiency and reliability of management decisions by conducting optimization directly on operating equipment. Based on the methods and approaches described above, new results have been obtained in the implementation of plasma technologies for the modification of geometrically complex surfaces of mechanical engineering products aimed at increasing wear resistance, hardness and other technical characteristics of the working surfaces of precision engineering products. A fairly complete approbation of methods, approaches, procedures and decision-making criteria for various technologies allows them to be recommended for universal applicability.
Science intensive technologies in mechanical engineering. 2024;(7):34-42
34-42
Science intensive technologies in machine assembly
MECHANICAL PRODUCT STRUCTURE
Аннотация
The structure of the product design affects the efficiency of its operation and the labor-output ratio. The structure of the product design can be represented using flat and spatial graphs, which are characterized by the number of levels and the number of elements located at each level, where both a node and a part can act as an element. Flat graph shows the connec-tions between the elements of the product design, their dependence, indicating the bases of each element, but at the same time it does not reflect their spatial location. The spatial graph illustrates the layout of the product structure in space. Hence, the structure of the product design should be understood as the relative location of the product design elements, their types and the number of each element. There is a direct connection between the structure of the product design and the level of its complexity. The more complex the product design structure, the higher the level of design complexity. Such connection allows
Science intensive technologies in mechanical engineering. 2024;(7):43-48
43-48