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One of the main reasons of the significant economic losses of consumers and suppliers of electrical energy is the use of low-quality electricity. In the event of such situation, the solution of financial compensation issue of damages to the injured party is based on determination of factual contributions of entities connected to power network to the deterioration of power quality at the point of common coupling. So far, there are many methods of determination of the factual contributions to the reduction of power quality that are different both in methodology and in technical features of their implementation. The results of analysis of the present methods and their classification are given and the application field of each of them is identified in the article. © 2015, Wydawnictwo SIGMA - N O T Sp. z o.o. All rights reserved.

Royanov V.A.,Pryazovskyi State Technical University | Bovikov V.I.,Azovobshchemash Company
Welding International | Year: 2016

The results of a review of literature data show that electric arc metallizing systems are characterized by high consumption of compressed air. Spraying is accompanied by the high-intensity interaction of the spraying air jet with the liquid metal of the molten ends of the electrodes, leading to rapid burnout of the alloying elements. The intensity of the oxidation reaction depends on the heat resistance of the sprayed material, the dispersion of the particles, the affinity of the components for oxygen and the technological parameters of the coatings. In order to reduce the oxidation effect, it is proposed to use a pulsed air-spraying jet. To solve this problem, experiments were carried out to develop appropriate equipment for the EN-17 stationary electric arc metallizing system characterized by the pulsed discharge of the air-spraying jet in the range 0–130 Hz. The experimental results show that the spraying jet is pulsed with temporary breaks. When using circular cross sections, the pulse smoothly becomes larger. The application of the right-angled section results in the pulse shape increasing at a higher rate. The experimental results show that the oxidation effect of the air-spraying jet is reduced. It is also shown that the optimum frequency resulting in improved properties of the coating is in the range 40–80 Hz. © 2015 Taylor & Francis.

Cheiliakh Oleksandr P.,Pryazovskyi State Technical University | Kolodyazhna Irina V.,Donetsk National University
Key Engineering Materials | Year: 2011

This work addresses an urgent problem which is saving alloying elements (Ni, Mo, Nb, V, W and others) -which very scarce in Ukraine and other countries-while increasing the physical, mechanical and operational properties of the new designed and developed wear-resistant cast irons. Optical microscopy, x-ray structure analysis, transmission and scanning (fracture) electron microscopy methods, different-thermal, magnetometric and x-ray analyses, as well as hardness and micro-hardness tests, impact energy, and abrasive wear tests in environments of cast-iron shots were employed in the research. The work summarizes the controlling conditions for forming various metastable phases by including deformation (or strain) induced phase transformation (DIPT) and through realization in the process of testing. New wear-resistant economical alloyed cast irons with a metastable austenite-carbide and austenite-martensite- carbide structure are developed, which are being strain-hardened under impact-abrasive wearing operation conditions due to the realization of process DIPT in the superficial layer. These new cast irons are intended for manufacturing parts of different equipment (protective plates of sinter machines, furnaces, tracks for transferring raw materials at iron and steel works, etc.). These cast irons do not contain expensive and deficit alloying components, like nickel, molybdenum, vanadium, and more expensive similar materials. Simultaneously they possess enhanced impact-abrasive wear resistance.

Bulgakova J.,Pryazovskyi State Technical University
Transport Problems | Year: 2013

The necessity of work-in-process management of rail-cars production by intelligent decision support software, which is based on JIT and Kanban principles, is identified. The scheme of one type cargo-flow movement between two workshops with control by electronic and traditional kanban-card is offered. For simulation of rail-cars production cargo flows Markov chain of M/M/1/1 type was applied. Simulation shows the dependence of the work-in-process on the in-flow and out-flow intensity. To determine the high level of the optimal work-in-process the stochastic inventory management model is applied.

Chabak Y.G.,Pryazovskyi State Technical University
Metallofizika i Noveishie Tekhnologii | Year: 2015

The results of study of phase-structural changes' kinetics in cast highchromium cast iron during ageing in the subcritical range of temperatures (350-700°C) are presented in a given article. The iron composed of 2.70% C, 2.20% Mn, 0.55% Si, 14.55% Cr, 0.93% Ni, 0.39% Mo, 0.38% V, and 0.11% Ti is studied. Using the microstructural method, the TTT-diagram of transformation of primary (as-cast) austenite is plotted. As found, within 25 hours of soaking, the austenite transformation occurs only in a range of temperatures of 550-700°C to form a fine eutectoid consisting of ferrite and cementite carbides having the fibrous or platelet shapes. Kinetics maximum of transformation corresponds to 650°C; the incubation period at this temperature is 5 minutes; the completion of the transformation is recorded after 8 hours of soaking. Formation of eutectoid at 700°C is accompanied by the precipitation of fine secondary carbides fromaustenite. Repeated heating of cast iron having fully eutectoid matrix at 650-700°C for up to 25 hours results in complete spheroidization and coagulation of eutectoid carbides. This leads to the formation of ferrite matrix with the granular carbides of mean diameter of 0.23-0.28 μm. The data regarding the influence of soaking time at 650-700°C on the number of eutectoid carbides of different shapes are presented in a given article. During repeated heating, the cementite type of carbides is not changed. The activation energy of coagulation of eutectoid carbides is calculated to be 73.1 kJ/mol. It indicates that rates of spheroidization and coagulation of eutectoid carbides are controlled by diffusion of carbon in ferrite. Because of doubled subcritical treatment, the microhardness of matrix reduces to 285-365 HV as well as bulk hardness reduces to 38-41 HRC that provides satisfactory machinability of cast iron.

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