SUMMARY. The influence of heterogeneity of the initial stress field on the propagation period and average velocity of the strain pulse in elastic continuum have been studied. The study was conducted for a case of non-uniform uniaxial stress field. Due to the iterative method the tensor stress components were represented on a certain segment as the sum of their mean-integral values and deviations from these values. The obtained zero-approximation solution depends only on the stress field mean-integral values. The correction of the solution at the first iteration depends both on the mean-integral values and stress components deviations. The obtained results allow to assert that the integral acoustic relations can be effectively used for formulation of inverse problems of a tensor fields tomography.

SUMMARY. The influence of heterogeneity of the initial stress field on the propagation period and average velocity of the strain pulse in elastic continuum have been studied. The study was conducted for a case of non-uniform uniaxial stress field. Due to the iterative method the tensor stress components were represented on a certain segment as the sum of their mean-integral values and deviations from these values. The obtained zero-approximation solution depends only on the stress field mean-integral values. The correction of the solution at the first iteration depends both on the mean-integral values and stress components deviations. The obtained results allow to assert that the integral acoustic relations can be effectively used for formulation of inverse problems of a tensor fields tomography.

SUMMARY. It has been shown, that the inaccuracies in the Сhichinadze mathematical model for the calculation of the temperature flash considerably decrease its applycation limits. New modification of this model for heat flow distribution coefficient between the solids under friction on the basis of Jaeger, Sharron, Blok formulas have been proposed.

SUMMARY. The high-temperature (650°С, 500 h) interaction of 20X13 chromium steel with stagnant lead melt saturated with oxygen (СO[Pb]  6∙10–3 mass.%) was investigated. At first (up to 200 h) the separate islands of oxide Me3O4 (Me: Fe, Cr, Pb) are formed on the steel surface, that with time (500 h) due to lateral growing covered steel completely by the double oxide layer. Outer oxide layer is complex oxide (Fe1–xPbx)O  Fe2O3 growing from the initial interface “solid metal–liquid lead” towards the melt. Inner oxide layer is Cr-rich spinel (Fe1–xPbx)O(Fe1–yCry)2O3 formed on the basis of matrix. Both layers grow symmetrically with respect to the initial interface “solid metal–melt”. Lead does not penetrate into the matrix and is fixed only in the oxide layer.

SUMMARY. An equation for calculation of the mean temperature of a conduit wall, depending on the density of heat flow and solution speed in the conduit has been proposed. It has been supposed that formation of corrosion products on copper and in the solution includes reactions, as the result of which copper complex compounds with components of the solution, solvated and desolvated oxides, and in these reactions a shift of dynamic equilibrium depends on temperature of copper surface are formed. In conditions of ion-exchange cleaning of 66 % ethylene glycol solution the coefficient of protective action (Z) decreases with the heat-flow rate increase and appropriate temperature increase of copper surface. Decrease of copper dissolution speed (Z > 40%) is achieved in 66 % ethylene glycol solution with specific resistance at the level of 25 km and concentration of dissolved oxygen of 0.9…1 g/m3.

SUMMARY. The kinetics of carbonitriding of c.p. titanium and OT4, BT14 titanium alloys during saturation from graphite in nitrogen has been investigated. It has been proposed to use nitrogen with oxygen impurities as a saturating medium. The oxygen plays the role of carbon transporter to titanium surface. It allows to intensify the phase formation as well as to obtain the carbonitrides at a low (up to 850C) saturation temperature. As result the surface microhardness increases and its roughness decreases. The additional diffusion of oxygen promotes the increase of the depth of gas saturation layer whereas the carbon diffusion increases the hardening efficiency.

SUMMARY. The influence of graphite phase parameters on the bending tensile strength of bending sag, and also the fracture intensity of manganese cast-irons and steels are analysed. The least wear was observed in the alloys, with graphite inclusions length of about 30...50 μm and hardness 250 HB. Decrease of alloys hardness and increase of graphite phase parameters, and also its amount (on the occupied area) to 6...10% results in the metallic matrix disintegration and in decrease of strength, intensification of fracture processes in the conditions of friction. It was found, that austenitic cold worked manganese steel unlike hard-tempered 40; 45; 45Г2; 20ХН steels capable in the conditions of the lack to of lubricant to retain on a surface a layer from the adsorbed layers of oil and graphite for 3...4 h.

SUMMARY. Electrochemical behaviour of nickel and cobalt in tungstate melt and the influence of electrolysis conditions on nickel (cobalt)–molibdenum (tungsten) alloys and intermetallides composition and structure in oxide tungstate melts are studied. It is shown that with the increase of molibdenum (tungsten) concentration and the decrease of nickel (cobalt) content in a melt the phase composition of cathode deposits consists of: nickel, cobalt, alloys and intermetallides of nickel and cobalt with molibdenum and tungsten, molibdenum, tungsten.

SUMMARY. The regularities of corrosion-electrochemical behaviour and selective dissolution of 12Х18Н10Т steel in ozonized 30, 40 and 70% H2SO4 aqueous solutions are investigated. Ozone retards steel corrosion to only 40%. In ozonized 30 and 40% H2SO4 solutions the speed of dissolution of nickel and chromium in corrosion of 12Х18Н10Т steel is reduced, the amount of dissolved chromium is twice as much as of the nickel. A hypothesis of ozone influence on dissolution of steel components through formation of ОН─ ions promoting oxidation of Fe, Cr up to higher valences and limiting the anodic process was proposed.

SUMMARY. The alternation of the active and passive periods of Ox/Red processes on the surface of electrodes of amorphous metallic Fe alloys was found out by the voltammetry method. The sequence of electrochemical reactions, allowing to explain the temporary periodicity of the change of currents and potentials of spontaneous dissolution of amorphous metallic Fe alloys, was proposed.

SUMMARY. It was established by DC electrochemical and impedance methods that addition of modified zinc phosphate to silicone based primer, generally used for protection of steel pipelines at the output from gas-compressor stations, provides increase of its protective properties and corrosion resistance. The possibility of improvenent of protective properties of silicone organic coatings by use of a blend of modified zinc phosphate and fine-dispersed omiacarb in their composition was shown.

SUMMARY. The technology of materials synthesis based on combined (self-propagating high temperature synthesis + metalothermy) process is described. Some theoretical problems of synthesis, as well, as technological peculiarities of combined processes are considered for the conditions of micromelting. Carbon steels were synthesized on the basis of the developed burden compositions, containing a link component – high-speed steel and the tungsten carbides. The parameters of carbide steels output out of the burden were established experimentally and peculiarities of microstructure, chemical composition, mechanical and technological properties of synthesized alloys were investigated.

SUMMARY. The research results of hydrogen effect on the characteristics of short-term strength and low-cycle life of austenitic stainless steels and dispersion-hardened alloys are compared. It is shown that solution hardened austenitic stainless steel 06Х20Н16Г6АФ with optimal nickel, manganese and nitrogen content have high strength and plasticity and minimal tendency to hydrogen degradation.

SUMMARY. Experimental data on the low-cycle durability of 22К steel and its welded joints – materials from which steam separators of NPP with the RBMK-1000 reactors are manufactured – are generalized. Experimental data are compared to normative dependence for carbon steels according to the current standard ПНАЕ Г-7-002-86. It is shown, that safety factors in evaluation of cyclic durability for a 22К steel separator are ensured. In this connection the service life of equipment of NPP of the first generation with the RBMK-1000 reactors, made from 22К steel was extended for 15 years.

SUMMARY. The cast two-phase steels in most widespread in industry and nature соrrosive environments: chloride, alkaline and hydrogen sulfide solutions has been studied. In contrast to austenitic steels cast two-phase steels can be considered as a perspective structural material for hot concentrated alkaline and low-concentrated chloride solutions. In the conditions with an increased chloride concentration the working stresses can be determined on the basis of the threshold values. Cast steels are not suitable for the use in hydrogenated environments.

SUMMARY. The results of electrochemical researches of ВТ5 titanium alloy, 12Х8Н10Т stainless steel and this steel with different wear-resistant coatings in solutions of acetylsalicylic acid (рН 2,6) and calcium gluconate (рН 6,8) are presented. In conditions of abrasive friction in technological medium the diamond-like carbonic coatings (DLC), which electrochemical behaviour is independent of the mechanical action on the surface have the highest protection properties against electrochemical corrosion.

SUMMARY. Structural and stress state of electric spark coatings has been investigated by X-ray method. The coatings were formed on the surface of У8 steel during treatment of hard-alloy electrode Т15К6. Residual stresses in different phase components differ by values and a sign. Subsequent laser heating led to decrease of the compressive and tensile residual stresses. Residual stresses relaxated fully in austenite thin layer on substrate due to decrease of specific phase volume under  transformation.