No 4 (154) (2024)
Materials science in mechanical engineering
WEAR RESISTANCE OF HEAT-RESISTANT STEELS HSM-7 AND HSM-10 AFTER ION-PLASMA NITRIDING, LOW-PRESSURE CARBURIZING AND LOW-PRESSURE CARBONITRIDING
Abstract
Tribotechnical characteristics of martensitic grade steels HSM-7 (16Cr2Ni3MoVNbNAl) and HSM-10 (13Cr3Ni3Mo2VNbNAl) were analyzed. Steels underwent ion plasma nitriding, low-pressure carburizing and low-pressure carbonitriding. The concept of a two-stage hardening technology has been implemented: the creation of a thermally stable finely dispersed state of steel at the first stage and the use of such a state for accelerated and qualitative saturation of the surface layer with nitrogen or carbon at the second stage. To create an ultra-finely divided state in the samples of steels under investigation, the method of intensive plastic deformation (IPD) was used. The method is based on the grinding of the microstructure due to large shear deformations. IPD was performed by the method of warm precipitation in a die with a degree of deformation of 80 % at a temperature of 700 ℃. The wear resistance tests of the samples were carried out on a special stand with reciprocating motion in the medium of a plastic lubricant material of mating samples having flat friction surfaces at a pressure of 10 MPa and an average velocity of 0,19 m/s. It is shown that HSM-7 and HSM-10 steels after ion-plasma nitriding and vacuum cementation have high wear resistance (wear intensity I 10-10). After low-pressure carbonitriding, the values of the wear intensity of the friction pair samples are almost the same and amount to 0,3·10-10, which is ~3,0 times less than after low-pressure carburizing. As a result of ion-plasma nitriding and low-pressure carbonitriding, a nanostructured surface layer is formed on steel surfaces contributing to wear resistance increase. The ideas concerning nitrided steel score resistance increase are given.
Science intensive technologies in mechanical engineering. 2024;(4 (154)):3-18
3-18
Technologies of mechanical processing of workpieces
MODELING CHARACTERISTICS FOR SURFACE FINISH WHEN MILLING STAINLESS STEELS USING VARIOUS MEDIA
Abstract
Modeling characteristics for surface finish when milling stainless steels using various media (grade steel 12X18H10T) using IOL-20A (industrial oil lubricant), CM-99 (cooling mixture), rapeseed and castor oils and on dry treatment, using the algorithms of the group method of data handling are viewed. The use of various lubricating and cooling technological mixtures (LCTM) is thought of as the theory of metal cutting factor reducing surface undulation. However, the degree of influence of various LCTM, including vegetable oils, when milling steel 12X18H10T has not been determined. The study case of various effects interaction on the milling process has shown that these studies were conducted on the basis of single-phase experiments that do not allow specifying mutual influence of the studied factors on the value of the parameters of the cutting process for various types of treatment. The research methodology provides for modeling surface finish under milling of 12X18H10T steel according to experimental data using various process liquids in the accepted range of cutting modes. At the same time, modern modeling methods allow us to determine these mutual effects. To obtain models, it is urgent, first of all, to be aware of break-in process criterion and dulling tool criterion as well. As a result of processing experimental data for each of processing media, surface finish models in the form of dependencies Ra = f (v, sz, t) were constructed, adequately describing the milling process with various media. It is indicated that the influence of regime parameters on the formation of micro-dimensions take the form of their close interrelation. Their interplay has various effects, depending on the LCTM used for the specified work stock and tool material.
Science intensive technologies in mechanical engineering. 2024;(4 (154)):19-28
19-28
Technological processes automated control
TRANSFORMATION OF THE INFORMATION STRUCTURE AS A TOOL FOR EFFICIENCY INCREASE IN HIGH-VARIETY PRODUCTION
Abstract
Characteristics of high-variety production enterprise are viewed, in particular: technological training, operational management and improvement of production efficiency. The issues of increasing the competitiveness of a high-variety production enterprise, determining the requirements for the processes of management and preparation of production with a focus on ensuring efficient loading of technological equipment, planning the operation of production sites while maintaining high flexibility, are highlighted. The key problems identified. The following ones can be noted: the lack of statistical information for calculations and planning in relation to the conditions of a particular production; insufficient level of interaction of services and production units; a static approach to managing a dynamic production system; lack of effective feedback channels that allow tracking the current production situation for appropriate analysis and giving necessary corrections. It is shown that the use of digital technologies and software has significant potential for solving problems in the considered production conditions. The existing means of digitalization make significant improvements possible in the level of interaction between departments and the interconnection of individual stages of preparation and operation of production, the availability of necessary information and quick delivery of it. The prospects for the development of the enterprise information environment for improving the efficiency of technological preparation of production and its operational management are identified. The necessity of having feedback channels that allow monitoring the current production situation for appropriate analysis and development of necessary corrections in the conditions of the stochastic nature of production processes and enterprise agility is determined. The practicability of integrating digital production systems based on adaptive management systems having technological intelligence into the information environment of an enterprise is reasoned out. Thus, the intellectualization of production requires the modernization of the principles of building information support for the production process.
Science intensive technologies in mechanical engineering. 2024;(4 (154)):29-40
29-40
Science intensive technologies in machine assembly
HIGH-TECH INCOMPLETE VEHICLE PRODUCTION
Abstract
In modern automotive production, high-tech robotic complexes and assembly lines are widely used for all four main production stages: pressing, welding, coating and assembly. The paper views industrial robot-assisted high-tech incomplete vehicle production using robotic manipulators. Studies have been conducted on the efficiency and productivity of automotive production through the use of a robotic assembly. Studies have been conducted on the efficiency and productivity of automotive production using a robotic assembly. A brief overview of scientific works on automation of production using robotic systems is presented. The discussed robotic complexes include various robots: assemblers, manipulators, auxiliary robots. The payback period of the robotic complex ranges from three to five years. Robotic complexes are successfully used in various factories, e.g. 115 robots are used at Volkswagen, 112 robots are used at Renault, 106 robots are used at Nissan. The average time period for assembling one basic vehicle product at the factory is 25 hours. The main characteristics of a robotic automobile assembly such as cycle of the assembly line; work pace; assembly line load factor are viewed. The influence of the main characteristics of the assembly line on productivity in robotic automotive production is estimated. The results show an increase in product output of up to 10% with an increase in the load factor by one tenth. The robotic assembly line efficiency calculation for automotive production shows that within five years the increase in net profit when using just one robotic assembly line will amount to about five million rubles. In addition, the output of products will significantly increase with RPA in automotive production. The effectiveness of using a robotized assembly line in automotive production is also shown.
Science intensive technologies in mechanical engineering. 2024;(4 (154)):41-48
41-48