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SCIENTIFIC AND TECHNICAL
Yushchenko K.A., Zadery B.A., Zvyagintseva A.V., Kushnaryova T.N., Nesmikh V.S., Polishchuk E.P. and Savchenko V.S. Application of nano-structured materials for diffusion bonding of heat-resistant nickel alloys 2
When joining structure-oriented or single-crystal heat-resistant nickel alloys, to maintain their performance it is necessary to retain as much as possible the structural and crystallographic orientation of the initial material in a resulting joint, which can be achieved by solid-state joining, e.g. diffusion bonding. The study considers the possibility of using for diffusion bonding a binding film of nano-structured crystalline monoliths of intermetallics Ni3Al and NiAl3, produced by the super-rapid solidification method, as well as an intermediate multi-layer film consisting of individual layers of nickel and aluminium, produced by vapour phase deposition. It is established that the presence of an intermediate layer allows intensifying the process of diffusion bonding of nickel alloys.
Ryabtsev I.A. Structural heredity in the initial materials–metal melt–solid metal system (Review) 8
Issues of structural heredity in the initial materials–molten metal–solid metal system are considered on the basis of literature data. It is shown that the solidified metal of ingot (deposited metal) inherits not only contamination of initial charge (electrode) materials by nonmetallic inclusions and other harmful impurities, but also elements of the crystalline structure of these materials. The use of ultrasonic treatment of the weld pool, as well as combined heat sources (hybrid technologies), such as arc-laser, plasma-laser, etc., is indicated to provide the equilibrium structure of the deposited metal.
Skulsky V.Yu. Features of d-ferrite formation on the fusion boundary in welding heat-resistant chromium martensitic steel 13
Possible mechanism of formation of decarburized d-ferrite grains in the fusion zone was studied by simulating the thermodeformation cycle of welding in a rigidly-restrained sample of heat-resistant steel P91 through heating with passing electric current up to surface melting, and by comparing the resulting structure with that of the actual welded joints. The suggested mechanism attributes formation of the above grains to appearance of regions depleted in carbon and rich in ferritizing elements, which results from liquation redistribution of alloying and impurity elements, as well as regions depleted in carbon in the grain bulk, resulting from its migration towards the weld.
Labur T.M., Taranova T.G., Kostin V.A., Ishchenko A.Ya., Grigorenko G.M. and Fedorchuk V.E. Influence of structural transformations in welding of aluminium alloy B96 on fracture resistance parameters 17
The nature of structural transformation occurring in aluminium alloy B96 during heating in welding was studied by scanning electron microscopy. The composition of the phases and their morphological peculiarities were estimated quantitatively and qualitatively, depending on the thermophysical conditions of nonconsumable electrode and electron beam welding. Effect of the volume content of phases on the processes of initiation and propagation of cracks under the conditions of off-centre fracture of samples of welded joints was evaluated.
Shah K.B., Kumar S. and Dwivedi D.K. Abrasive wear behaviour of Fe–Cr–C overlays 22
Present paper describes the influence of number of passes on abrasive wear resistance of Fe–Cr–C hardfacing on mild steel. Overlays were deposited by a gas metal arc (GMA) welding processes using a commercially available surfacing electrodes of 4.0mm diameter. Overlays were deposited using welding current of 160 A. One, two and three pass coatings were developed using DCSP at constant welding speed of 15 cm/min. The abrasive wear resistance of overlays was evaluated on a pin on disc system against a 320 grade SiC abrasive medium at two normal loads of 2 and 10N. Wear pin of 6Ф6Ф20mm size was used for abrasive wear test. Optical microscopy was used to study the microstructure of overlays. SEM studies of wear surface were carried out to analyze the wear mechanism. Increase in number of welding passes increases the abrasive wear. Variation in the hardness across the interface was noticed.
INDUSTRIAL
Kovtunenko V.A., Gerasimenko A.M. and Gotsulyak A.A. Selection of steel for critical building welded structures 27
High-strength sparsely-alloyed steel 06G2B meets the current requirements to materials for critical metal structures applied in construction and mechanical engineering. Comparative analysis of steel 06G2B and other steels usually used in the local metal structures has been performed. Results of investigation of service properties of 06G2B rolled stock and welded joints are presented. It is shown that the steel has a certain potential for application in fabrication of critical metal structures.
Garashchuk V.P. Technological characteristics of laser beam for cutting and welding 32
An analytical expression of depth resolution was derived through the beam parameter product and its angle of convergence with the assumption that the caustic surface of the focused beam has the shape of a single-cavity hyperboloid of revolution. For practical use of the derived relationship, formulas of the beam parameter product in resonators and lasers applied in practice are given.
Astakhov E.A., Borisov Yu.S., Kaplina G.S., Kokorina N.N., Ipatova Z.G. and Chernyakov O.F. Effect of heat treatment on structure of amorphised detonation Fe–B coatings 35
The effect of heat treatment (HT) in a range of 200–650 °C on the process of crystallisation of the amorphous phase (AP) in detonation coatings deposited from powders of amorphising Fe–B alloy with a particle size of < 40 and 40–63mm was investigated. It is established that the AP content of a coating deposited from a fine powder is 32 vol.%, and that of a coating deposited from the powder with a particle size of 40–63 mm is 57 vol.%. Heating to 500 °C leads to complete crystallisation of AP in both cases. Microstructure of coatings was investigated, and they were tested to gas-abrasive wear resistance after HT at different temperatures. Maximal increase in wear resistance (by 35–40 %) was achieved at a structural state of the coatings corresponding to crystallisation (~ 3 % AP).
Patyupkin А.V. and Antonyuk D.A. Forecasting cavitation-corrosion resistance of deposited metal of Fe–Cr–Ni–(Mo) alloying systems in 92 % solution of sulfuric acid 39
An empirical dependence is proposed of the influence of the main alloying elements in complex-alloyed stainless alloying systems (Fe–Cr–Ni–(Mo)) on cavitation-corrosion resistance of the deposited metal in the concentrated solutions of sulfuric acid.
BRIEF INFORMATION
Zhadkevich M.L., Tyurin Yu.N., Kolisnichenko O.V. and Mazunin V.M. Characteristics of pulsed plasma flow in plasma-detonation generator at different flow rates of fuel mixture 42
Thermal and gas-dynamic characteristics of a supersonic pulsed plasma flow depending upon the degree of filling of an inter-electrode gap with a fuel mixture were calculated on the basis of analysis of the results of theoretical studies of the plasma-detonation unit.
Zhudra A.P., Krivchikov S.Yu. and Petrov V.V. Effect of graphite on kinetics of transfer of carbon to weld pool in flux-cored wire cladding 43
Given are the results of investigations into the effect of grain size composition of graphite powder in the core of a self-shielding flux-cored wire on absorption of carbon by the weld pool and arc stability in electric arc cladding. It has been established that the maximal value of the coefficient of transfer of carbon to deposited metal and high arc stability can be achieved by using the electrode graphite with a grain size of 200–250 mm in the flux-cored wire core.
In memory of Dr. Sossenheimer 45
Theses for scientific degree 46
Developed at PWI 21
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