Установление характеристик горячей деформации высокопрочной стали HC420LA по результатам испытаний на сжатие
The high-strength steels (HSLA) used in such fields, which require light and reliable design. First of all, it's machine-building industry. The aim of this paper – on the basis of obtained data, after carried out a tests using hot deformation of steel HC420LA, obtain parameters which describe its mechanical properties. This is necessary to determine the optimal technological production regimes.
The object of the study is the activity of the enterprise during the long-term period and its management through the simulation system. The purpose of the work is to create the structure of the simulation system and tools for managing the activities of the enterprise. In the course of the work, various management strategies and their impact on the development of the enterprise were studied. A system has been developed that allows creating strategic plans for each subsystem of the enterprise and 32 monitoring the impact of decisions on results. It was found that an increase in the amount of investment in a strategy tool is effective only to a certain extent. The results of the work can be useful in teaching the development of strategic plans and enterprise management.
The purpose of this work is the development of a core and a module for working with strategies for planning the development of a hotel complex. In the future these ready-made materials are suitable for creating a simulation system that can greatly simplify and accelerate the management and development of hotels of different levels. Also, the structure of hotels has been examined in detail, and the main tasks of strategic development have been singled out. The composition of the tasks is determined, ensuring the fulfillment of the set goals according to the given criteria. Strategies have been developed for the practical implementation of these tasks. The end product is a program that gives users the opportunity to determine the strategies of their enterprise that would meet the goals and criteria of these goals.
The increasing of the efficiency of technological modes of steel products manufacturing requires simulation of metal forming during hot deformation. To obtain correct results, one should set the correct initial and boundary conditions, including the mechanical properties of materials, which represent the dependence of the stress-strain and strain rate at maintained temperature. In the experiments one must reveal the mechanical properties and constants of the steels according to strain rate, predetermined temperature and chemical composition. So, the type of test is usually dependents on the technology process, which simulation will be using the obtained information. One can identify four main types of tests used in the hot deformation: compression, tension, torsion and rupture tests. The simplest tests are considered as uniaxial compression or tension tests. The results of these tests are the curves of <<flow stress -- strain>>. The present study describes an approximation method of test results for uniaxial compression of cylindrical samples made from AISI304 steel. During this work a mathematical model of the <<stress -- strain>> relation has been described. An algorithm that determines the necessary numerical coefficients for this model was developed. As a result, the equation of the material state, which is characterized by the stress relation on the strain, strain rate (0.15, 0.5, 1.5, 5 and 15 inverse seconds) and temperature (800, 950, 1080 and 1200 degree Celsius) was found. Also the approximation comparison with the experimental results were obtained.
The subject of the research is developing of simulation system of enterprise management. The aim of this work is development of enterprise management model and the following realization of software, which allows user to simulate possible ways of enterprise development in the long run. Interface and functional part of the marketing subsystem were designed with using the mathematical model of marketing and enterprise management model was studied during the research. Programming language C# was used for the software developing. The result of the work is the study of the mathematical model of enterprise management in the marketing subsystem and the creation of software that allows to consider and test a variety of options for the development of the enterprise in terms of the chosen efficiency criterion, for example, the profit maximization for a long period of the enterprise.
The swelling and mechanical properties of vanadium and V-Ti (10-35 at. % Ti) and V-Ti-Cr (20 at. % Ti, 10 at. % Cr) alloys after neutron irradiation in the BOR-60 fast reactor to a total fluence of 1023 neutron/cm2 in the temperature range 350-830°C are studied. The samples are irradiated in sealed lithium-filled ampules. The swelling of the vanadium and alloy samples after irradiation is no more than 0.2%. Adding 10-35 at. % Ti to vanadium suppresses the low-temperature radiational embrittlement of the alloy; this effect is greatest with 35 at. % Ti. In the temperature range 700-1000°C, high-temperature radiational embrittlement appears in the alloy with 35 at. % Ti, but not in the alloy with 10 at. % Ti. Simultaneous alloying with 20 at. % Ti and 10 at. % Cr leads to the appearance of low-temperature radiational embrittlement of the alloy. The variation in the mechanical properties of the alloys on neutron irradiation is analyzed, taking account of the phase diagrams, and the limiting titanium and chromium content in the alloy is determined