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Danilov V.N.,Central Research Institute for Machine Building Technology
Russian Journal of Nondestructive Testing | Year: 2010

On the basis of an earlier developed model on scattering of transverse waves at a crack in the form of a strip, exact and approximate (estimated) scattering indicatrices for transverse and longitudinal elastic waves are studied, taking into account the influence of their transformation at the flat free surface of a reflector into other wave types on the change in the Echo-signal amplitude. The limits of applicability of the estimated indicatrices for mirror and back reflections are numerically studied. The exact results for longitudinal waves are compared to those obtained by the Kirchhoff method. © 2010 Pleiades Publishing, Ltd. Source


Danilov V.N.,Central Research Institute for Machine Building Technology
Russian Journal of Nondestructive Testing | Year: 2010

Some features in the formation of the signals of a normal linear transducer with a phased array are studied. The characteristics of the signals from a normal linear transducer with a phased array and a radiating element in the form of an elongated rectangular piezoelectric plate are compared. It is shown how much the amplitude of a signal that is focused and radiated along the acoustic axis exceeds that of a signal from a conventional transducer with an extensive radiating element. An analytical equation describing the dependence of the signal amplitude on the distance along the focusing direction at a specified angle to the acoustic axis is deduced. © Allerton Press, Inc., 2010. Source


Danilov V.N.,Central Research Institute for Machine Building Technology
Russian Journal of Nondestructive Testing | Year: 2010

The acoustic path of an angle transducer is calculated in the Kirchhoff approximation for a reflector of the flat-bottom-hole type. The formula obtained can be used for constructing DGS diagrams. In the limiting case of the far-field zone, an asymptotic formula is obtained for the acoustic path confirming the validity of using analogous relationships, which were heuristically obtained earlier. Numerical calculations of the DGS diagram of an angle transducer are performed, the results of which are compared to those obtained via the recalculation of the diagram for a normal transducer. © Pleiades Publishing, Ltd., 2010. Source


Nikulin I.,Belgorod State University | Kaibyshev R.,Belgorod State University | Skorobogatykh V.,Central Research Institute for Machine Building Technology
Journal of Physics: Conference Series | Year: 2010

Tensile properties of the 18Cr-9Ni-W-Nb-V-N austenitic stainless steel were studied at strain rates ranging from 6.7×10 -6 to 1.3×10 -2 s -1 in the temperature interval 20-740°C. It was found that this steel exhibits jerky flow at temperatures ranging from 530 to 680°C and an initial strain rate of 1.3×10 -3 s -1. This phenomenon was interpreted in terms of Portevin-Le Chatelier (PLC) effect occurring due to dynamic strain aging (DSA). PLC yields significant increase in high temperature strength of this steel due to extending of plateau on temperature dependence of yield strength (YS) and ultimate tensile strength (UTS) to higher temperatures. As a result, YS and UTS remain virtually unchanged with increasing temperature from 350 to 740°C. Role of additives of tungsten and vanadium in DSA and high temperatures strength of the austenitic stainless steel is discussed. © 2010 IOP Publishing Ltd. Source


Kaibyshev R.O.,Belgorod State University | Skorobogatykh V.N.,Central Research Institute for Machine Building Technology | Shchenkova I.A.,Central Research Institute for Machine Building Technology
Metal Science and Heat Treatment | Year: 2010

Prospects of commercial use of new-generation martensitic thermomechanical steels created on the basis of Fe-11% Cr steels are considered. The physical causes of degradation of mechanical properties in the process of creep of these steels at > 590°C are studied in detail. It is shown that the degradation is connected with formation of the Z-phase. The mechanisms of formation of the phase are described. © 2010 Springer Science+Business Media, Inc. Source

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