Time filter

Source Type

Cheiliakh Ya.O.,Pryazovskyi State Technical University | Cheiliakh O.P.,Pryazovskyi State Technical University
Metallofizika i Noveishie Tekhnologii | Year: 2016

The model of formation of the chemical and phase compositions as well as the structure of wear-resistant deposited Fe-Cr-Mn metal with evaluation of its metastability, depending upon surface deposition and technological parameters of facing, is proposed. The layer-by-layer mechanism of formation of the chemical and phase compositions of the deposited metal is discover; it provides different metastability of austenite and could be quite efficiently modified by the degree of layers' melting.

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.

Kukhar V.V.,Pryazovskyi State Technical University
Metallurgical and Mining Industry | Year: 2015

The finite element simulation of changing the stress-strained state parameters and simulation of the indices of the plasticity reserve usage at the new technology of producing of elongated parts with sharpened end by the longitudinal rupture and local heating of a workpiece was done. The comparison of the indices of the plasticity reserve usage was made with the application of various methods. A research of macrostructure and technology approbation in industrial conditions confirmed satisfying technological heredity of products that produced by considered method. © Metallurgical and Mining Industry.

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.

Parunakjan V.,Pryazovskyi State Technical University | Sizova E.,Pryazovskyi State Technical University
Transport Problems | Year: 2013

Existing systems of transportation service of metallurgical enterprises are considered and the need for logistical management of production-and-transport system of enterprises is substantiated. For this purpose principles of development of logistical chains that provide efficiency in interaction between production and transport are worked out. Copyright © Wydawnictwo Politechniki Śla{ogonek}skiej Gliwice 2013.

Efremenko V.G.,Pryazovskyi State Technical University | Shimizu K.,Muroran Institute of Technology | Noguchi T.,Muroran Institute of Technology | Efremenko A.V.,Pryazovskyi State Technical University | Chabak Y.G.,Pryazovskyi State Technical University
Wear | Year: 2013

A wide range of heat treated iron-based alloys (steels and white cast irons) was subjected to wear test in laboratory mill with the aim of discovering the correlation between microstructure type and impact-abrasive wear resistance under corrosion. The role of microstructure and chemical composition was identified through analysis of wear behavior under a range of slurries (pH 1-14) and analysis of the worn surface. It was found that the best wear performance is achieved with martensitic structure in steels containing not less than 13. wt% Cr. The results showed that austenitic Cr3Ni, Cr3Mn and Mn-based steels do not demonstrate significant advantages in wear resistance over low-alloyed steels having martensitic microstructure. It was found that high-chromium white cast irons have average wear resistance because of embrittlement due to the presence of coarse eutectic carbides in the structure. It was also noted that wear resistance depends both on corrosive resistance and deformation resistance. Deformation resistance seems to play a more important role because it can largely compensate for the lack of corrosion resistance. It was concluded that low-alloyed hypereutectoid steel having "martensite-austenite-carbides free" microstructure could be considered the most effective alloy for use in wear application, taking into account its low cost. © 2013 Elsevier B.V.

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.

Ivanov V.,Pryazovskyi State Technical University | Lavrova E.,Pryazovskyi State Technical University
Applied Mechanics and Materials | Year: 2014

The technology and equipment for pulsed feed of strip electrode for electric arc cladding was developed. The influence of transfer control parameters on the electrode melting process was investigated. Found that pulsing feed of the strip electrode provides optimum heat input into the base metal, stable penetration without defects of the bead formation. © (2014) Trans Tech Publications, Switzerland.

Efremenko V.G.,Pryazovskyi State Technical University | Chabak Yu.G.,Pryazovskyi State Technical University | Brykov M.N.,Kharkiv Polytechnic Institute
Journal of Materials Engineering and Performance | Year: 2013

This study presents kinetics of precipitation of secondary carbides in 14.55%Cr-Mn-Ni-Mo-V white cast iron during the destabilization heat treatment. The as-cast iron was heat treated at temperatures in the range of 800-1100 °C with soaking up to 6 h. Investigation was carried out by optical and electron microscopy, dilatometric analysis, Ms temperature measurement, and bulk hardness evaluation. TTT-curve of precipitation process of secondary carbides (M7C3, M23C6, M3C 2) has been constructed in this study. It was determined that the precipitation occurs at the maximum rate at 950 °C where the process is started after 10 s and completed within 160 min further. The precipitation leads to significant increase of Ms temperature and bulk hardness; large soaking times at destabilization temperatures cause coarsening of secondary carbides and decrease in particles number, followed by decrease in hardness. The results obtained are discussed in terms of solubility of carbon in the austenite and diffusion activation of Cr atoms. The precipitation was found to consist of two stages with activation energies of 196.5 kJ/g-mole at the first stage and 47.1 kJ/g-mole at the second stage. © ASM International.

Nazyuta L.,Pryazovskyi State Technical University
Metallurgical and Mining Industry | Year: 2015

This work provides an analysis of the mechanism of iron deoxidation with titanium based on the experimental and theoretical data. Depending on the titanium content in liquid melt Fe-Ti-O, the oxides are formed with different valences, which are of different crystal lattice structure: TiO (face-centered cube), TiO2 (tetragonal lattice), Ti2O3 (trigonal of α-alumina type) and Ti3O5 (orthorhombic). The thermodynamic characteristics of the basic process of deoxidation in the case of formation of each of these oxides, including deoxidation constant and interaction parameters at 1600 °C, was analyzed. It is shown that the basic difficulties in determining of these parameters are associated with the identification of the reaction products, since the same content of titanium in the liquid melt, as well as the use of similar techniques provide the various oxides formation. Experimental data on the equilibrium constants KTiO2, KTi3O5, KTi2O3 differ by almost 2 orders of magnitude. The authors try to adjust the inaccuracies in the deoxidation constant determination by the parameters of the interaction. It should be noted that the data of different authors thermodynamic calculations of deoxidation constant for each oxide (regardless of the method of their calculation) differ slightly. At a temperature of 1600°C, their value according to different authors is relatively stable: KTiO2-1 = (5.1-7.0)·10-7, KTi3O5-1 =(4.1-4.6)·10-18: KTi2O3-1 = 2.7·10-11. The studies by D. Yanke and B. Fisher using probes based on ThO2 - Y2O3 when measuring of oxygen activity are the most reliable. At a temperature of 1600°C, in the titanium content range of 0.001-0.1%, the value of the equilibrium constant is ΚTi3O5 = 7.41·1018 (the inverse value 1.35·10-19) according to their studies, and in the Ti content range of 0.1-3%, the value of the constant is significantly lower ΚTi2O3 = 3.7011 (the inverse value 2.70·10-12). The main reason for discrepancy between the theoretical and experimental data is the lack of a reliable method of the interaction parameters calculation that take into account the oxygen activity impact on the system. Interaction parameter eTiTi, which average value is 0.041, is relatively reliable. Effect of titanium on the oxygen activity is ambiguous. If the titanium content is less than 0.2%, in the case of TiO2 formation, an interaction parameter will be eOTi = - (0.160 - 0.187), in the case of Ti3O5 formation, eOTi = - (0.31 - 0.37). If the concentration of titanium in the liquid melt is more than 0.2% (Ti2O3 formation), its effect on the oxygen activity increases, the interaction parameter increases almost twice and is eOTi = - (0.65 - 0.75). © 2015. Metallurgical and Mining Industry.

Loading Pryazovskyi State Technical University collaborators
Loading Pryazovskyi State Technical University collaborators