Abstract: In the article is shown the comparative analysis between structures of surfaced by the flux coded wire metal systems Fe-C-Si-Mn-Cr-Ni-Mo-V and Fe-C-Si-Mn-Ni-Mo-W-V. These powder wires are supposed to be used in recovering details and equipment components and machines, that works in conditions of intensive abrasive – shock wear. Manufacturing and surfacing of flux cored wires samples were made in laboratory conditions. Defined chemical composition of the surfaced metal. Deposited metal samples hardness and wear resistance were researched. In the course of deposited meta surface metallographic analysis were made following metallographic researches: defined nature and level of nonmetallic oxides impurity, type and morphology of the microstructure, grain size of surfaced samples. Estimation of the chemical composition components influence on the hardness and wear resistance were obtained.
Abstract: The physical models of the induction crucible furnaces with nonconducting crucible and conducting crucible were developed. Experimental study of the parameters of an induction crucible furnace for melting of ferromagnetic lumpy charge in ferromagnetic nonconducting crucible was made. Experimental study of the parameters of the furnace for melting copper and magnesium in conducting crucible was made. Three-position control system of active power of induction crucible furnace for melting of ferromagnetic lumpy charge and two-position control system for temperature regime of induction crucible furnaces with conductive crucible were developed.
Abstract: The authors complete calculations of the boundary of adsorption lines of CO and CO2 molecules under the limited volume. The cells with the transverse size from 10 to 200 nm are considered. The inaccuracy of the half-breadth of the lines appearing when the cylindrical and spherical cells are modeled with rectangular cells was estimated. When calculating the shifts and the half-breadth of the lines of CO and CO2 molecules the authors consider the model in which CO and CO2 molecules adsorbed on the walls of the pore may cease their rotational motion.
Abstract: The tests were carried out to identify the influence of electropulse treatment on austenite steel ((mass %) 0.44С, 16.50Mn, 0.26Cr, 0.08Ni, 0.34Si, 2.74Al, 0.002S, 0.017P, Fe – balance). The fa-tigue life is reported to increase by 1.8 times. Electron microscopic research into the dislocation structure of the steel was conducted under diverse fatigue conditions with the purpose to give rea-sons for the identified effect. The dislocation chaos substructure, reticular and fragmented dislocation substructures were found in the steel in the initial state. Fatiguing leads to the change in the dis-location substructure parameters. The subsequent electropulse treatment furthers transformation of the grain structure since grains arise and grow due to evolving local dynamic recrystallization and partial transformation of the dislocation substructure and occurrence of a great number of microtwins. The increase in the fatigue life is associated with the mentioned above transformations resulting from electropulse treatment of the steel structural state.
Abstract: The paper presents the results of the X-ray diffraction analysis of structural-phase states in the weld zone of a titanium alloy Grade2 in micro-and submicrocrystalline states. It is established that the structural-phase state in the weld zone and in the heat-affected zone depends on the state of samples of the alloy Grade2 before welding. It is shown that formation process of metastable phases ω-Ti and α′′-Ti occurs in the submicrocrystalline state in the alloy Grade2 in the weld zone and in the heat-affected zone. Investigations of the features of the microhardness distribution in the weld zone in alloys Grade2 in micro-and submicrocrystalline states are carried out. Different character of microhardness distributions in the weld zone in the samples depending on the structural-phase state of welded plates made of alloy Grade2 is determined.
Abstract: The structure and microhardness of high-speed steels P6M5, P9 and P18 after electron-beam processing were investigated in the work. Electron-beam processing was carried out on the industrial accelerator ELV-4. It was established that electron-beam processing allows to obtain a modified layer on the surface of fast-cutting steels with thickness of 20 μm with high hardness, consisting of fragmented martensite with fine carbide particles. It was determined that after electron beam processing the microhardness of high-speed steels increased to 9.5 GPa. It has been experimentally established that the growth of hardness and wear resistance of high-speed steels after electron-beam processing is the result of the formation of more fragmented martensite and a decrease in the size of carbide particles.
Abstract: The paper describes the basic principles and some results of obtaining data by means of integral strain gauges about load-carrying capacity and durability of gear transmissions for new specimens of machines when running in the transmissions in structure of gear box on the stand, or in short-term trials of machines in field conditions.
Abstract: Rail welded joints are integral part of continuous welded rail. However, they often do not have sufficient reliability during the operation. The article is devoted to the assessment of temperature influence effect on the mechanical properties and structure of weld metal and welded rails. The temperature distribution across the rail section in welded zone during the cooling process of aluminothermic rail welding is obtained using simulation by LVMFlow. The results of the study of hardness and structure of metal rail aluminotermitic welded joints are given. It is shown that the hardness of rail welded joints increases from 24 HRC to 38 HRC in the fusion zone of the weld metal and rail metal. It is due to the harmful effects of overheating of the metal during the welding process. The hardness is confirmed by microstructural analysis. Microstructural analysis showed the differences in the grains sizes of metal welded zone and heat affected zone. The structure of welded metal is acicular dendritic. Owing to a difference between structures of the welded joint zones the probability of occurrence of cracks on the boundary of fusion weld and metal is increased.
Abstract: Surface modification of silumin of the grade AK12 with plasma formed during an electrical explosion of aluminum foil with a sample of yttrium oxide powder placed in the explosion region (the electroexplosive doping method) is carried out. The thermodynamic analysis of the system Al-Si-Y-O is carried out. The phases formed in this system under equilibrium conditions are revealed. Investigations of the elemental and phase composition and the defective substructure are carried out. Mechanical (microhardness) and tribological (wear resistance and friction coefficient) tests of the modified material are performed. The physical mechanisms responsible for multiple enhancement of surface properties of the modified silumin samples are revealed.