[en] Proposed is a method of tests of ring samples of many-layer tubes, which simplifies considerably the test process and provides deriving strength characteristics (σsub(β) and σsub(0.2)) with a considerable high accuracy. On examples of six-layer tubes of the 28x1.2 mm size of the 08Kh18N10T steel shown is that the proposed method permits to reduce the consumption of many layer tubes 10 times in comparison with longitudinal tests of one-layer samples. Presented are the strain distribution epures according to thickness and length of one-layer and six-layer tubes as well as mechanical properties of tubes in transverse and longitudinal directions

[en] Determination technique of the critical coefficient of stresses intensity for steels of medium strength possessing rather high plastic properties is developed using as an example samples of the 15Kh2NMFA steel grade. The tests are performed with the recording of the P-v diagrams (force-shift). It is shown that the experimental data obtained reaffirm the expedience of the use of ''deformational'' approach during selecting the allowance for non-linearity of the force-shift diagram depending on the sample thickness in the cases when the fracture analysis points to the absence of noticeable subcritical growing of cracks

No abstract available

[en] Using the ESR method amount of V₄⁺ ions in vanadium pentoxide and ammonium metavanadate powders calcinated at 523 K is determined. Determination limit when EPA-2 spectrometer is used constitutes 2x10^-₂ %, accidental error of the determination at small amounts (<= 0.1 %) does not exceed 9x10^-₃. Duration of one determination is 5 min. It has been established that dispersion of the products in organic media (ethanol, benzene) results in the increase of V₄⁺ ions

No abstract available

No abstract available

[en] Technique for determination of aluminium impurities in niobium pentachloride was developed. The technique is based on aluminium separation by solvent extraction with isobutanol in the form of dibromohydroxyquinolinate and on its successive determination in the organic phase with the use of trihydroxyfluorone. The effect of accompanying elements was studied. Metrological characteristics of the technique were determined. The lower boundary of determined concentrations is 1x10^-4% Al

[en] Direct spectrophotometric method of > 0.001% REE determination in steels based on the interaction of arsenazo 3 and REE in aqueous-ethanol solutions (60% vol. C₂H₅OH) is described. To increase selectivity the reaction is carried out at pH=1.0-1.5 in the presence of considerable excess of arsenazo 3. The effect of interfering elements is removed adding complexon 3 and H₂O₂. The time of single sample analysis is 2-3 h

No abstract available

No abstract available