Mechanical properties of the metal from drums of boilers at the Starobeshevskaya and the Lugansk thermal power plants (TPPs) were investigated. According to the results of the standard technical diagnostics and a strength analysis, both drums comply with the applicable regulatory requirements. At the Starobeshevskaya TPP, the drum was ruptured during a hydraulic test. It was found that this was caused by the low impact strength of the metal at room temperature. The objects of the investigation were fragments of the ruptured drum and a “plug” cut out of the shell during a scheduled inspection. An attempt is made in this paper to assess the state of equipment metal based on the results of tests on subsize Charpy specimens. It has been demonstrated that when standard Charpy specimens (10 × 10 × 55 mm) cannot be made but impact bend tests have to be performed, the brittle-to-ductile transition temperatures for standard Charpy specimens may be obtained in testing 2 × 8 × 55 mm specimens. The correlation developed to relate the test results from subsize specimens to standard Charpy specimen enables us to assess in the first approximation the fitness for service of the metal to prolong the equipment’s service life. The rupture surface of subsize Charpy specimens has almost the same appearance as that of standard specimens. The temperature dependence of ductile component of subsize specimens agrees well with the corresponding dependence for standard Charpy specimens. To integrate the test data into a single database, it is desirable to derive a correlation to relate the critical brittleness temperature from a subsize specimen test to the critical brittle temperature from standard Charpy specimens.

A comparative investigation of the metal of drums of two TP-100 boilers at the Starobeshevskaya and the Lugansk thermal power stations (TPS) was performed. Their operation time was approximately 300000 hours; the shell of one drum was ruptured during a hydraulic test, and the other drum is in operation. According to the results of the technical diagnostics and a strength analysis, both drums comply with the applicable regulatory requirements. The objects of the investigation were fragments of the ruptured drum and a “plug” cut out of the shell during a scheduled inspection. The investigation was carried out by microscopic metallography methods and the scanning electron microscopy technique. Mechanical tests of metal specimens were performed, and the hydrogen content in these specimens was measured. Prior to the material research, the metal was examined using a magnetic memory method. The investigation yielded specifics of the metal microstructure, mechanical properties, and fracture patterns of the metal specimens at various temperatures. An investigation performed by the method of thermal-desorption mass spectrometry revealed no considerable difference in the hydrogen content in the metal of both drums, thereby excluding the effect of hydrogenation in analyzing the rupture causes. It was established that the drum at the Starоbeshevskaya TPS had been damaged due to its low impact strength at room temperature and high brittle-ductile transition point. Comparison of the metallographic study data with the results obtained using the magnetic memory method suggests that the fracture was caused by local formation of the Widmannstatten pattern at points where accessories are welded to the shell. The prospects are demonstrated of the comprehensive approach to nondestructive examination (NDE) of TPS drums using the magnetic memory technique and metallographic methods.

Here is given the results of investigation of mechanical properties of high-purity hafnium, iodide hafnium and hafnium GFE-1 at temperature range 20-900°C. Taken results are testifying about considerable influence of methods of receiving hafnium, its purity and mechanical-thermal processing on mechanical properties. The characteristic abnormalities of mechanical properties in the temperature range 20-900°C for different purity hafnium are discussed.

Here are presented the results of investigations of temperature dependence of mechanical properties of a high-purity hafnium, produced by zone melting, in temperature range of 20...800 degrees C. The significant differences in strength and plasticity characteristics, and also in peculiarities of temperature dependence of those characteristics in comparison with known analogues for technical hafnium are revealed. Discussion of obtained results is presented.

MECHANICAL CHARACTERISTICS OF Zr1Nb ALLOY TUBE AFTER DEPOSITION OF ION-PLASMA COATINGS V. A. Belous, P.N. V'ygov, A.S. Kuprin, S.A. Leonov, G.I. Nosov, V.D. Ovcharenko, L.S. Ozhigov, A.G. Rudenko, V.T. Savchenko, G.N. Tolmacheva, V.M. Khoroshikh The paper presents the results of studies of the effect of ion-plasma coatings on the mechanical properties of the Zr1Nb alloy tube segments. The samples were tested in tension after deposition single-layer (TiN), multilayer (Ti+TiN)(x), (Zr+ZrN)(x), and multicomponent nanostructured TiAlN, TiAlSiN, TiAlYN condensates. The test results showed that the deposition of coatings increases the tensile strength sigma(B) of 12 to 21%, at a constant yield strength sigma(0,2). It is shown that the film thickness of about 5 mu m have a high hardness and strength. Maximum hardness (45 GPa) on the surface of the Zr1Nb alloy is obtained after deposition of nanostructured condensate Ti77,9Al19,2Si2,7N, and the greatest increase in sigma(B) corresponds for samples coated by (Ti+TiN)(x).

Experimental results of obtaining microlaminates with maximum number of layers 1620 and of study of structure and properties of these composites are described. Experimentally established dependence of the mechanical characteristics of microlaminates on the number of layers and heat treatment parameters is presented. The mechanism of relationship between structure and mechanical characteristics of microlaminates and model of their evolution during heat treatment of composites is suggested.

Mechanical properties of made from the GFE-1 metal hot-rolled hafnium plates during deformation tension are investigational. The anisotropy of microhardness of material is defined on the different planes of the rolled plates. The microstructure of hafnium plates after rolling and after annealing at the temperature 1173. during a two clocks is studied. A structure after rolling testifies to flowing of partial recrystallization, while after annealing it becomes fully recrystallizativeCorrelation between the temperature of tests, fracture pattern of specimens and plastic characteristics of material by a raster electronic microscopy is disclosed. Texture researches of hafnium plates suggest that hafnium rolling at a temperature 1123 K to results in development typical for HCP metals of base-prismatic type texture with predominance of base component.

Dependences of vacancies clusters concentration in materials was investigated in real time for different radiation condition: neutrons flux density and clusters lifetime depending on temperature of environment. Dependence of density vacancies clusters sinks on their life-time (the environment temperature) and on neutrons flux density allows to select the radiation conditions for materials: according to the define radiation it is necessary to determine the parameters of material standard treatment before its placing in the core.