[en] Effect of the chloride concentration and medium pH on the cyclic resistance to cracks of structural steels is investigated with the aim of provision for their operation reliability. The steels are studied in the nuclear reactor water of boron control with NaCl and HCl additions at 300 deg C. It is shown that the main mechanism of effect of oxygen-free reactor water with operating parameters on the resistance to crack of NPP materials is hydrogen embrittlement of the metal decrushing zone whereas the anode solution is an attendant factor. 19 refs., 4 figs

[en] A technique for determination of strength characteristics in welded joints of dissimilar materials is suggested. The technique is based on loading by concentrated forces applied to crack sides. To realize such loading a machine is designed that permits to produce fatigue cracks on separation surface of contacting metals in a special specimen. The precracked specimens are tested on static tension under different angles of load application with recording a load-crack opening curve. The investigation into cracking resistance of a Kh18N10T steel - AMg6 aluminium alloy composite is carried out according to the technique suggested

[en] On the samples of 15Kh2NMFA, 15Kh2NMFAA and 10GN2MFA vessel steels tests for corrosion cyclic crack resistance in water of high parameters (350 deg C, 18MPA), imitating by composition NPP primary circuit medium, are carried out. Increase of crack propagation under water tests as compared to tests in air, and also with increase of asymmetry coefficient of loading cycle is detected. Occurrence in fracture of brittle sections is noticed. An equation for estimation of crack propagation velocity is suggested

[en] A method is considered for indirect evaluation of fracture toughness Ksub(1c) in large-sized pieces of ductile steels through testing welded specimens containing mild interlayers of these steels. The method is based on the existance of relationship between constraint of plastic strain in mild interlayers and fracture toughness. Results of testing specimens with interlayers of carbon and Kh18N10T steels are presented. A nomogram is plotted to choose optimum dimensions of specimens and interlayers for Ksub(1c) determination in metals. Comparison of Ksub(1c) values obtained on testing integral specimens and welded specimens with interlayers shows their satisfactory coincidence within experimental data scattering

No abstract available

[en] Proposed is an analytical criterium for estimating the conditions of brittle fracture of metals on the base of the hypothesis that brittle fracture begins not in the crack mouth, but at some distance in the plasticity zone, if the shear tension characteristic to the metal under study is attained. The steel samples of the Kh8N10T type with the V-shaped concentrator have been made. The fracture toughness (Ksub(s)) of the Kh8N10T steel determined by the ''fast'' crack stop is 22% less than Ksub(s) estimated by the conventional method. The experimental data confirm the applicability of the proposed analytical criterium for brittle and for rather plastic metals in a wide temperature range as well

[en] Consideration is being given to the basic hypotheses, explaining the effect of aqueous solutions on the rate of crack propagation (RCP). It is shown that the effect of corrosion medium reduces with the growth of change of stress intensity factor. It was concluded that for each value of range of stress intensity factor its own critical frequency of loading exists, below which the increase of crack propagation rate can't be expected. Forms of cycles were systematized with respect to effect on RCP in aqueous media, and the maximal value of cycle asymmetry increasing RCP was established

[en] The dependence of fatigue crack growth rate on the amplitude of stress intensity coefficient for 08Kh18N10T steel in boron regulated reactor water was investigated. Insignificant increasing of the crack growth rate in water at 573 K temperature in comparison with air at 293 K was shown. The results prove the model of crack growth due to anodic dissolution

[en] On the basis of literature data generalization a possibility for the construction of a quantitative model predicting the effect of different factors (loading frequency, cycle asymmetry, shape and amplitude) on the crack growth rate in metals under the action of active corrosion water media, high temperatures and pressures has been considered. A limited set of experimental investigations, which is necessary to carry on for determining the lifetime of articles according to the model suggested, has been recommended

[en] The basic statements of express-method are formulated for estimation of high-temperature effect upon fatigue cracks growth rate in thermostable steels from data on specimens tests in the same environments at normal temperature and cathodic polarization