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The paper presents the distribution of the strength characteristics of weld metal in heat-resistant steel 10GN2MFA over the thickness and height of the hot collector-to-nozzle welded joint in NPP steam generator determined by the instrumented indentation test method. [ABSTRACT FROM AUTHOR]

The results of investigations of the mechanical characteristics of molybdenum and niobium alloys and their welded joints, which are used in space-rocket hardware, have been generalized. The investigations were carried out under short-time, sustained static and low-cycle loading conditions on small time bases in a temperature range of 290-2270 K. [ABSTRACT FROM AUTHOR]

The results of investigations of the mechanical characteristics of tungsten, alloys and composite materials based on it, which are used in space-rocket hardware, have been generalized. The investigations were carried out under short-time, sustained static and low-cycle loading conditions on small time bases in a temperature range of 290-3020 K. [ABSTRACT FROM AUTHOR]

For a copper-tungsten microlayered composite material for electrical contact applications, which is prepared by electron-beam evaporation-condensation, the changes in its structure, conductivity, hardness, and mechanical properties in tension at room temperature and elevated temperatures are studied versus the tungsten content and heat treatment conditions. New morphological features of the condensed composite and the related changes in the material properties have been revealed. The conditions for the formation of structural defects and their influence on mechanical properties and fracture behavior of the material in tensile tests have been investigated. A relationship has been established between the tungsten content of the composite, its structure, strength, and hardness. [ABSTRACT FROM AUTHOR]

We investigate the structure, hardness, strength, plasticity and fracture character of Cu–Cr microlayer composite material for electric contacts with prescribed microlayered structure and chemical composition in the temperature range from 290 to 1070 K. The correlation relationships between the hardness and strength characteristics have been established. [ABSTRACT FROM AUTHOR]

We present the results of calculations of the kinetics of stress-strain state and stress intensity factors for surface and under-the-cladding circumferential cracks in modeling the emergency core cooldown conditions for the WWER-1000 reactor. The calculation procedure is based on a mixed finite-element method statement which provides stability of numerical solution and a high accuracy of results for both the displacements as well as stresses and strains. The authors analyze the influence of the density of the finite-element discretization of the crack-tip area for the surface and under-the-cladding circumferential cracks on the accuracy and convergence of computation of fracture-mechanics parameters in the modeling of thermal shock conditions. The results of calculation of kinetics of stress intensity factors allowing for the thermomechanical loading history and residual process-induced stress fields are reported. It is demonstrated that if the elastoplastic deformation history and residual process-induced stress fields are disregarded in the calculations of stress intensity factors for under-the-cladding cracks the reactor pressure vessel strength and lifetime may turn out to be overestimated. [ABSTRACT FROM AUTHOR]

A computational scheme has been developed and a numerical simulation of the stress-strain state near the crack tip is performed at different levels of the stress intensity factor using a compact tensile specimen as an example. The authors analyze the influence of the finite element size near the crack tip and compare the results obtained in different codes (software packages) for different crack geometries. [ABSTRACT FROM AUTHOR]

Charpy impact tests were conducted at different temperatures and loading rates. Temperature dependences of the crack initiation and propagation energies were determined for carbon steel 45, steels St. 3 and 15Kh2NMFA from the load-time curves obtained with due account of the impact test results. The effect of the loading rate on the temperature dependence of the impact toughness was analyzed within the range from 1 to 4.4 m/s. [ABSTRACT FROM AUTHOR]

The short-term static strength and momentary creep characteristics of low-alloyed molybdenum alloy VM-1 are investigated in the temperature range from 1820 to 2270 K. The creep strength values for the alloy were obtained for residual strain tolerances of 0.5 and 1.0%, the test durations of 102, 103, and 104 s at temperatures of 1820, 2120 and 2270 K. The empirical functional dependence is proposed to describe the correlation relation between the characteristics of short-term static strength, plasticity and momentary creep of the material in the thermomechanical range under study. [ABSTRACT FROM AUTHOR]

Results of numerical analysis of stress intensity factors KI for semielliptical surface cracks in the WWER-1000 reactor pressure vessel by emergency cooling simulation with known engineering procedures, the equivalent spatial integration and direct methods are presented. Engineering procedures employ the results of numerical solution of axially symmetric boundary value problems of thermoelasticity based on the mixed mesh-projection scheme of the finite element method implemented in the RELAX software. The three-dimensional KI computations were performed with the SPACE software. [ABSTRACT FROM AUTHOR]

Results of estimation of the stress-strain state appearing in the header-steam generator connector weldment after thermal treatment used for the reduction of residual welding stresses are presented. Such treatment, including heating, holding, and cooling of a local connector area with the weld joint, is shown to give rise to rather high additional residual stresses in the weldment. [ABSTRACT FROM AUTHOR]

The Charpy impact tests were carried out at different temperatures and loading rates. The temperature dependences of crack initiation and propagation in carbon steels 45 and St. 3 under impact testing were determined from the obtained force variation plots. The effect of the impact velocity in the range from 1 to 4.4 m/s on the fracture toughness temperature dependence is estimated. [ABSTRACT FROM AUTHOR]

A multichannel system of high-speed recording of strains and loads during fracture toughness tests of materials has been developed. A four-channel analog-to-digital converter was used to record signals. Tests were carried out using a rotary and a vertical impact testing machines at various loading rates and temperatures. Some results are presented for impact testing of Charpy specimens with recording of load variation at supports during tests. [ABSTRACT FROM AUTHOR]