编号 2 (2024)
Materials science in mechanical engineering
STUDY OF ORGANIC COMPOUNDS EFFECT ON SAMPLES MICROSTRUCTURE OF LASER POWDER SURFACING FOR SMFE POWDERS IN A MAGNETIC FIELD
摘要
The paper presents two main directions for improving the efficiency of permanent magnets (PM), by changing chemical composition of the future magnet and through variations of magnetic field shape. Increasing the efficiency of PM by changing chemical composition over the decades has made it possible to reduce multiply the size of the final product. In turn, increasing the efficiency of PM by alternating the magnetic field shape is a relatively new direction. Based on the analysis of the presented methods for increasing the efficiency of PM, it is proposed to use additive technologies, namely laser powder surfacing for the manufacture of permanent magnets. To conduct experimental studies, the KUKA robotic complex and permanent magnets are used as a source of a permanent magnetic field. The paper presents some modes of laser powder surfacing of Sm and Fe powders. A complex of six neodymium magnets is used to maintain a magnetostatic field. Strength distribution of the magnetizing field between the magnets and in the main working area is described. The external view and condition of the powders used for the manufacture of experimental samples are presented. Experimental samples and selective approach for analyzing the microstructure and concentration spectra of elements are described. The microstructure and distribution of elements in the obtained samples were studied depending on the texture of the sample relative to the magnetic field and laser surfacing mode. The effect of the applied organic binders on the microstructure and chemical composition has been determined. The distribution of elements in the samples and the transition layer between the support plate and the deposited metal is studied.
Science intensive technologies in mechanical engineering. 2024;(2):3-11
3-11
Technologies of electromachining and combined processing
EXPLORATORY STUDY FOR OPTIMIZATION OF THE CHOICE OF ULTRASONIC EQUIPMENT FOR THE DEPOSITION OF FUNCTIONAL COATINGS
摘要
To meet the requirements affecting the quality of functional coatings, various technologies are currently being used, one of which is the use of ultrasonics. To form functional coatings, ultrasonics are used both at the stage of surface preparation and at the stage of coating deposition. Thus, at the stage of surface preparation, ultrasonics allow making surface preclean, ensuring the necessary surface roughness due to ultrasonic rolling, as well as preactivation of the surface before nitriding due to surface plastic deformation. In case of coating deposition, ultrasonics contribute to better nitriding and painting. However, ultrasonic equipment used in various preparation and coating deposition processes differs significantly in its characteristics. Thus, the ultrasonic generators vary in alternator capacity, specific material consumption, actual frequency, as well as design features that ensure stable operation, for example, automatic frequency control. The converters differ from each other in accomplishable amplitudes, power and actual frequency. In this regard, the aim of the work is to develop recommendations on the use of ultrasonic equipment in various technical processes for the creation of functional coatings. The paper studies ultrasonic equipment used in surface preparation and functional coating application process. The main process-dependent parameters aimed at choosing the required equipment have been characterized. Recommendations are given on the use of ultrasonic equipment for various functional coatings generation, when a converter-generator couple is found and it meets the requirements for most surface preparation and coating deposition processes.
Science intensive technologies in mechanical engineering. 2024;(2):12-19
12-19
TECHNOLOGY AND RESULTS OF STUDYING THE SURFACE INTERACTION FOR CHARGED PARTICLES FLOW IN LOW-TEMPERATURE PLASMA
摘要
An analysis of approaches to studying the interaction of the surface with a stream of charged particles is presented in order to increase the efficiency of the process of low-temperature plasma modification of the surface layer. The results of the analysis showed that it is theoretically difficult to study the interaction, therefore, it is interesting to study it empirically using electrochemistry methods that allow us to investigate the phenomena of mixing and spreading of a liquid placed on the surface caused by molecular interaction processes. An off-the-shelf technology for studying surface interaction for charged particles flow in a low-temperature plasma has been found. The technology is based on the surface interaction for a particle flow simulator, using an aqueous 3,0 % NaCl salt solution. During the course of studying, it was found, firstly, that the results of interaction are actively influenced by chemical processes between the surface and the ions of the solution, depending on the value of the potential of the electric field applied to the surface, as well as due to its microrelief, and secondly, that the main boundary process running under surface interaction and solution is adsorption. The data of the analysis of the effects of exposure to the plasma surface are presented. They proved the reliability of study results, since the course of chemical and adsorption processes also take place. In general, the materials presented in the article allowed making conclusion that the developed technology makes it possible to determine the conditions that ensure an increase in the efficiency of the low-temperature plasma modification process contributing to the improvement of both surface (electrochemical) and volumetric (physical mechanical and electrophysical) properties if it is used either in the initial state or in the state changed by plasma particles.
Science intensive technologies in mechanical engineering. 2024;(2):20-27
20-27
Surface layer quality, contact interaction, friction and wear of machine parts
FORECASTING AND ASSESSMENT OF TRIBOTECHNICAL EFFICIENCY OF THE NITRATION CASE OF MACHINE PARTS
摘要
Following the laws of tribology and tribotechnics, also the results of experimental studies of reality of structure and properties change in the zone of contact tribodeformation of structural steels and alloys of different structural classes subjected to nitriding, an approach to forecasting and comprehensive assessment of the tribotechnical efficiency of nitriding of structural materials and products made of them has been developed. Analysis of the patterns of changes in the structure of the diffusion zone of nitriding steels: abnormal, martensitic and austenic, and relative wear resistance tests, taking into account their composition and technological parameters of the treatment process, showed that maximum wear resistance was provided by a nitration coating containing hardening dispersed particles of incoherent nitrides, ensuring a lower liability to brittle behavior of the nitration case due to low level of matrix level microdeformation. At the same time, preliminary types of treatment (thermal treating and deformation processing) of nitriding steels contribute to structural and phase state of the surface layer, which has added tribological performance. For nitrided ferroalloys with different matrix lattices, the most significant characteristics of the structural state and properties of the surface layers affecting the level of surface fracture under friction have been found empirically: the particle size of nitrides of alloying elements, the distance between them, the density of their distribution, the matrix lattice microdeformation, the values of X-ray lines intrinsic broadening for structural components of the material in the friction deformation zone, the hardness of the nitration case and its changes under friction. These experimental results are taken as a principle of the proposed method for forecasting and assessment of metal tribotechnical efficiency. This principle of method is based on a tribological criterion containing micro- and macroscopic characteristics of the material in the zone of contact deformation under friction, the choice of fabricating methods for the product takes place to ensure an acceptable level of wear intensity. Then, by measurement, using surface large deformation method, the ability of the nitration case formed as a result of treatment according to the selected treatment schedule to perceive surface nondestructive plastic deformation is evaluated. It affords a basis for the selected nitriding treatment schedule. The completion of the assessment is the determination of the values of the maximum operability of the nitriding material under conditions of friction and wear (alarm pressure when a tribocouple operates steadily; critical pressure when it is inoperable, but its operation is possible with short-term overloads; the average total wear intensity of the couple combined). The totality of the identified parameters allows recommending the material, its working and predicting operating modes and durability of tribounit.
Science intensive technologies in mechanical engineering. 2024;(2):28-40
28-40
Technological support of operational properties of machine parts and their connections
ROBOTECHNICS IN THE AIRCRAFT INDUSTRY
摘要
Some cses of robotized systems and complexes (RS and RC) in the aircraft industry are considered. A robotic cell for resistance spot welding is viewed, the main components of which are an industrial robot (IR), welding guns, a linear displacement module of IR, an inverting unit. Here the IR performs welding, it is equipped with welding guns as a hand. An inverting unit equipped with a stepper motor rotates the panel around the axis and sets the part to be welded within the whole welding process. The movement of the IR is also carried out due to the linear displacement module. The robotization of harnesses production is viewed, using automatic lofts and collaborative robots, which, moving along specialized lofts, with the help of a linear displacement module, install holders on the loft and ties wires into harnesses. After the operation is completed, made-up harness is put into a storage hopper. A robotized complex (RC) for manufacturing parts of the «rib» type is studied. It includes a machine equipped with a vacuum gripper, technological equipment, consisting of a cutting machine and a bending press. The technological process has two stages: cutting and bending. The cut blanks are blown out of the press onto the receiving tray. The IR performs feeding of blanks into the working area of the technological equipment and laying in the appropriate storage unit. 3D models of robotized sites are presented, their components are listed. In conclusion, the importance of analyzing the process operation is proved, when the feasibility of robotization is evident. An algorithm for analyzing the process operation is presented. It has been understood that the introduction of robotics in certain technological processes reduces the impact of hazardous production factors.
Science intensive technologies in mechanical engineering. 2024;(2):41-48
41-48