Rheological characteristics of steel in continuous roll casting-rolling

Problems. In the process of obtaining a strip in a casting and rolling device, the question arises of combining the process of hot rolling of the solidified material and the process of crystallization of the liquid melt. This makes it possible to implement an efficient technology for producing thin-sheet products. Purpose of the study. Determination of rational parameters for performing mathematical modeling of material behavior during roll casting requires clearly defined recommendations. The material for the rolling process is steel. The starting material was used in solid, solid-liquid and liquid states. Implementation technique. The analysis of the properties of steel was carried out on the basis of the results of experiments obtained at the Physico-Technological Institute of Metals and Alloys of the National Academy of Sciences of Ukraine. To analyze the rheological properties of steel, the dependences of the yield stress for alloyed and carbon steels were used in a certain temperature range. The selected temperature range includes solidus and solid-liquid state of steel, located above 0.8 melting point. Research results. Based on the research results, the analysis of the rheological properties of steel in solid, solid-liquid and liquid states during continuous casting-rolling on rolls was carried out. The use of the obtained dependencies makes it possible to perform mathematical modeling of the deformation and hydrodynamics of the material during continuous casting-rolling of steel strips using roll casting-rolling devices. Conclusions. The constructed dependences, together with studies of the viscosity of steel in the liquid state and the resistance of steel to deformation in the solid state, most fully describe the rheological properties of steels during casting-deformation processes. The obtained dependences will make it possible to implement an ultra-efficient technology for producing thin-sheet rolled products.

DEVELOPMENT OF AN AUTOMATED DESIGN SYSTEM FOR FLEXIBLE AUTOMATED PRODUCTION

Design of flexible manufacturing systems (FMS) of modern multi-level production is usually carried out on the basis of general rationing when using large recommendations. At the same time, the specifics and features of a particular production are not always taken into account. In such a design, the most important is the experience of the designer, which is not always based on modern methods of optimizing project solutions. Therefore, the problem of creating automated design systems in the development of flexible automated productions (FAP), which use cost equipment with numerical control (CNC) is extremely urgent. The development of automated design systems is based on the ideas of a systematic approach that determine different cycles of the process: design - production preparation - production. Information about the projected object is generated in the process of project development by different groups of users: researchers, designers, designers, technologists, production organizers. A multilevel, cyclical design process requires the use of such a volume of information that cannot be processed without the use of modern mathematical methods and calculated equipment. Therefore, it is extremely important to create automated gap design systems, which are marked by greater versatility, efficiency and possibility of development, improvement and adaptation to the conditions of various enterprises. Such requirements served as the basis for the creation of an automated design system , which allows to take into account a huge amount of information in the automatic cycle during the development of the project. The scientific novelty of the work is the development of an integrated automation system for the design of processing technology and the selection of elements of FMS structures. At the same time, information unity with the system of technological training of production at the level of operation of FMS is ensured.

Creation of Sealed Strong Structures of Rocket and Space Equipment FDM Printing Methods by Ultem ™ 9085 Pei Plastic

The work shows the possibility of manufacturing products for rocket and space technology using the additive FDM-printing technology. The object of research is the nozzle plugs of the "membrane" type. Considering the specific-strength properties of the product during its operation during operation, as well as the features of the FDM-process, the design was optimized, the regularities of the formation of its properties were established. An impregnation technology has been developed to seal the product. The equipment was designed, and pneumatic tests were carried out. The properties of materials were investigated considering their guaranteed shelf life for 12 years of operation under accelerated climatic tests. It is shown that the production of products by FDM-printing methods is promising and expedient, since the properties being formed are predictable, achievable, and stable.

Frequency response function simulation and evaluating in boring

Finite element method of simulating frequency response function (FRF) for boring tool in LS-Dyna solver is investigated in this work. Nowadays, computer numerical simulation allows to obtain FRF using different materials model with high precision compared to real experiments with sensors like impact hammer testing. This function is used in construction of stability lobe diagrams that allows operator of machining center to avoid chatter self-excited vibrations. Such vibration is led to decreasing of productivity and quality in cutting of metals and other materials. Amplitude and phase angle for the model is obtained from LS-Dyna result interpreter, that reads binary files, created during simulation by the program. Amplitude and phase angle of frequency response function are depending on dynamic stiffness of machining system. Real and imaginary part of frequency response function have been obtained during simulation. With luck of dynamic stiffness amplitudes of response increases.

Processes and technologies of cold gas dynamic spraying of products agricultural equipment

Modern equipment of processing industry, animal husbandry, bioenergy complexes is used for processing, storage or transportation of aggressive substances. Functional coatings made of inert materials do not enter into any chemical reactions with food, processed products, livestock waste, acids and other aggressive media. There is a question of protection of the equipment of the processing industry, animal husbandry, bioenergy complexes from aggressive environments by application of processes of a cold gas-dynamic spraying. This is an urgent problem for the development of protective technologies and appropriate equipment for the implementation of the process of creating functional coatings

Kinetics of Damage of Materials under Various Regimes of Re-Changeable Loads

Kinetics of accumulation of damages in engineering objects, which work at repeated-alternating soft and hard modes of loading of details and elements of constructions of vehicles (cars, cars, railway transport, etc.). When changing the direction of the load force to the opposite in the structural material there is a phenomenon of changing the kinetics of accumulation of damage, ie the damage factor at separation and shear changes, which affects the effective stresses and service life of equipment. This effect of the factor of the influence of repeated variables on the redistribution of the kinetics of damage accumulation is considered experimentally for materials with different plastic properties

Cold stamping of a cartridge case blank for 40x53 mm caliber grenade launcher ammunition

Problems. The choice of a rational method for stamping blanks with two hollows is usually carried out according to the permissible degree of deformation, the coefficient of material utilization, and the productivity of the process without taking into account the effect of the deformation pattern on the final mechanical properties of the stamped semi-finished product. Purpose of the study. Determination of a rational method for stamping a blank of a 40x53 mm grenade launcher cartridge case based on the results of computer modeling using the finite element method. Cartridge case material - AD35 aluminum alloy. The workpiece has two hollows with different diameters and depths. Implementation technique. By means of computer modeling using the finite element method, two options for stamping of a workpiece are researched - double-sided extrusion and sequential reverse extrusion with tilting of the workpiece. Research results. Based on the results of the research, the features of deformation according to the given schemes, as well as the energy-force parameters and parameters of the stress-strain state of the processes, are determined. It has been established that both methods make it possible to obtain blanks with specified geometric dimensions. At the same time, sequential back extrusion provides a more uniform and predictable deformation of the material along the cross-section of the workpiece, but loses in productivity to double-sided extrusion. Conclusions. The obtained research results can be used as criteria when choosing the optimal option for stamping of a workpiece with two hollows by cold extrusion.

Aggregative Methodology of Aircraft Cooperative Production Project Efficiency Evaluation

The overview of modern forms and trends of international cooperation in aviation industry is presented. The actuality of choice of cooperation schemes and main indices values of cooperation production for the aviation industry of Ukraine is determined. The analysis of dependences of key technical and economic indices of the Project of creation of aircraft cooperative production is carried out and the aggregative methodology of estimation of aircraft cooperative production project efficiency is offered.

Finite element analysis of electroresistive heating of a high pressure apparatus for studying the solubility of GaN in Fe

The advantages and disadvantages of methods for gallium nitride crystals production are considered. The convergence of the solution of the problem of electroresistive heating at determination of a thermal condition of the high pressure apparatus cell is investigated. The thermal state of the high pressure apparatus cell used to determine the solubility of gallium nitride in iron has been modeled and investigated. It is determined that the combined discretization with the use of triangular and quadrangular elements allows to reduce the time of solving the coupled problem of electrical and thermal conductivity under these conditions. The results of calculations are presented by steady temperature fields in various elements of the device. It was obtained that at the temperature in the cell control point of 1800 °С its axial difference in the volume of the investigated sample of iron was 62 °С , the maximum difference was 156 °С. The simulated cell configuration and the heating conditions defined for it are acceptable for experimental studies of the solubility of GaN in contact with Fe under conditions of high pressures and temperatures.

Ivchenko-Progress Se State and Prospects of its Development

May 5, 2021 marked the 76th anniversary of the foundation of Zaporizhzhia Machine-Building Design Bureau Progress State Enterprise named after Academician H. Ivchenko (Ivchenko-Progress SE). On May 5, 1945, by order No. 193 signed by the People's Commissar of the Aviation Industry of the USSR O. Shahurin a research and development bureau (RDB) was established at the State Union Plant No. 478 in Zaporozhye to develop new and update earlier designed medium and low power aircraft engines for civil aviation.