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ROLE OF TEMPERATURE IN HYDROGEN-INDUCED
CRACKING OF STRUCTURAL STEELS AND WELDED JOINTS I.K. POKHODNYA, S.N. STEPANYUK and V.I. SHVACHKO |
2 |
| A procedure is proposed for experimental study of the influence of hydrogen on mechanical properties of the metal in a broad range of temperatures. Temperature dependencies of the degree of hydrogen- induced embrittlement for St.20 and 17KhGNDSM steels in the temperature range of 196+400oC are determined. It is shown that, alongside the structural state, content and distribution of hydrogen, stress level and straining rate, temperature is the main initial factor determining the process of hydrogen embrittlement. | |
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DETERMINATION OF RESIDUAL
LIFE OF WELDED STRUCTURES WITH CREVICE-TYPE DEFECTS B.E. ANDREYKIV and M.V. LISHCHINSKA |
8 |
| The calculation model is suggested for investigation of the kinetics of propagation of fatigue cracks in plates whose material is heterogeneous in mechanical characteristics and resistance to fatigue fracture. The model is based on an energy criterion of fatigue fracture of materials. The system of differential equations has been derived to study the kinetics of growth of fatigue cracks in heterogeneous plates. Two problems in the determination of a period of sub-critical growth of a fatigue crack are considered: for a butt-welded plate and a cruciform welded joint. It is shown that the calculated service life values are in good agreement with the experimental dat | |
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APPLICATION OF EXPLOSION ENERGY
FOR IMPROVING RELIABILITY OF WELDED STRUCTURES V.G. PETUSHKOV |
13 |
| The essence, peculiarities and application fields of a new technology of explosion treatment of welded joints used to improve reliability and extend life of metal structures are outlined. Physical mechanism of the process and methods used for calculation of parameters of explosion loading of different-geometry weldments are described. Explosion treatment is shown to have a favourable effect on performance of welded structures and characterized by high productivity and cost effectiveness. | |
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EFFECT OF COMPOSITION OF SHIELDING
GASES ON TECHNOLOGICAL CHARACTERISTICS OF ARC DURING NON-CONSUMABLE ELECTRODE
WELDING OF ALUMINIUM ALLOYS A.Ya. ISHCHENKO, V.P. BUDNIK, A.G. POKLYATSKY and A.A. GRINYUK |
17 |
| Experiments on using neon and its mixtures with argon as a shielding gas in non-consumable electrode welding are considered. Data are obtained on weld formation, penetration and also volt-ampere characteristics at direct and alternating currents. The feasibility of using neon separately or in mixtures of gases for protection of aluminium alloy welding zone is shown. | |
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MATHEMATICAL MODELLING OF
THERMAL STATE OF THE BONDING ZONE BETWEEN DISSIMILAR METALS IN GLOW-DISCHARGE
DIFFUSION BONDING G.P. BOLOTOV, D.I. KOTELNIKOV and A.F. ROGOVOJ |
21 |
| The determinate mathematical model of the ion heating process has been developed on the basis of analysis of distribution of heat flows within the zone of contact between dissimilar materials. The model allows temperature of the bonding zone in bodies of the simplest shape (cylinder, parallelepiped) to be related to the process parameters and characteristics of the billets. The error in the calculation of temperature using this model is no more than 15%. | |
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IMPROVEMENT OF HEAT AND WEAR
RESISTANCE OF PARTS USING THE METHOD OF THERMAL SPRAYING OF COATINGS OF
CHROMIUM-BASED ALLOYS V.F. GORBAN |
25 |
| Effect of initial state of chromium-based materials used for thermal spraying on the properties of coatings is investigated. Interrelation between physical-chemical properties of coatings and technology of spraying and their effect on service characteristics of chromium coatings are studied. | |
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DEVELOPMENT OF THE TECHNOLOGY
FOR THE MANUFACTURE OF ARTILLERY STEEL CARTRIDGES AND BOTTOMS BASED ON
HIGH-TEMPERATURE INDUCTION BRAZING L.I. BONDARENKO and L.G. PUZRIN |
30 |
| Economical technology based on high-temperature induction brazing for the manufacture of cartridges and bottoms is suggested. Peculiarities of the technology are described and characteristics of the brazed joints are given. | |
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L.I. BONDARENKO and L.G. PUZRIN
ARGON-ARC SURFACE QUENCHING - METHOD FOR HARDENING ARTILLERY BARRELS L.I. BONDARENKO and L.G. PUZRIN |
33 |
| Surface quenching using concentrated heat sources and travel speed of the source needed to heat a layer of the required thickness and hardness are considered. The method, equipment and operational parameters have been developed for argon-arc surface quenching of the inside surfaces of barrels. Quenching of the full-scale barrels for the service life tests has been conducted. | |
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STRUCTURE AND PROPERTIES OF
HYPEREUTECTOID GRAPHITIZED ROLL STEEL AFTER PLASMA HARDENING S.S. SAMOTUGIN |
35 |
| Structure, hardness, impact toughness and character of fracture of hypereutectoid steel 150KhNM under dynamic loading after plasma hardening, as compared with volumetric quenching, are investigated. Hardness and impact toughness of steel after plasma hardening are higher than after volumetric quenching, which is caused by a highly dispersed martensite-carbide structure formed by plasma treatment. Fracture of metal of the hardened zone occurs by the mechanism of dispersed quasi-cleavage, while that of metal after surface micro- and macro-melting occurs by the mechanism of intercrystalline cleavage. | |
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ELECTRON BEAM REMELTING OF
OPERATING SURFACE OF EXHAUST VALVES OF AIRCRAFT ENGINES A.V. BONDAR, M.V. ERYOMIN, S.N. FYODOROV and V.V. SHURUPOV |
39 |
| Problems of repair of flaws of a discontinuity type, which are formed in a layer of the operating surface of aircraft engine exhaust valve, surfaced with a flame method, is considered. It is shown that, when using electron beam treatment with an ellipsoid scanning of beam, the flaws are eliminated in the deposited surfaces. During electron beam treatment the inner structure of the deposited layer is changed by refining and reorienting chromium carbides that increases the microhardness of the working surface. | |
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APPLICATION OF HEAT SINKS
FOR REDUCTION OF WELDING STRAINS AND STRESSES (Review) A.I. GEDROVICH and A.B. ZHIDKOV |
41 |
| The possibilities of controlling the strains and stresses in the joints with artificial heat sink are considered. Classification of welding processes with heat removal by the technological and physical features, is proposed. It is found that for up to 3mm thick metal the most effective is the application of the heat-absorbing pastes and crystalline heat-absorbing rods, and for 3-8mm thick metal it is water cooling. Welding with heat sink should be regarded as a resources-saving proces | |
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SELECTION OF EQUIPMENT FOR
MECHANIZED ARC WELDING, SURFACING AND CUTTING V.A. LEBEDEV and V.F. MOSHKIN |
45 |
| The results of analysis, development and selection of equipment for mechanized arc welding, surfacing and cutting are considered. It is shown that the intuitive approach to selection and development of the semi-automatic machines can lead to non-rational solutions. Methods of system approach are suggested which allow performance of a highly objective analysis and selection of the equipment, lowering the probability of taking wrong decisions, also at the stage of development of new semi-automatic machines. Selection of modular design using a basic model as a principle allowing development of semi-automatic machines for various purposes with rational technical and service parameters, is substantiated. | |
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PROSPECTS OF UTILIZATION OF
A HARD COMPONENT OF WELDING AEROSOLS A.A. ENNAN, P.A. IVANCHENKO and G.N. SHIKHALEEVA |
50 |
| New feasibility of utilization of a hard constituent of welding aerosol is described. Realization of a directed vapour-phase synthesis with producing highly dispersed powders of a preset composition and a developed surface of a phase contact will, probably, open up new prospects in the field of creation of materials of different functional purposes. | |
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