Ultrasonic nondestructive testing by head waves: Physical prerequisites and practical use

In 1972, studies on ultrasonic testing of metals from equipment at nuclear power stations performed at TsNIITMASh revealed a phenomenon of excitation of longitudinal waves with angle probes and their further propagation along the contact surface. This phenomenon was further comprehensively studied and called head waves in ultrasonic nondestructive testing of metals. Head waves have found use in practical ultrasonic testing both in Russia and abroad. This paper presents some principal points of the development of the theory and practice of ultrasonic testing by head waves.Translated from Defektoskopiya, Vol. 40, No. 9, 2004, pp. 27–37.Original Russian Text Copyright © 2004 by Razygraev.This paper is based on the materials reported by the author at the International Forum of Specialists of Universities, Research Institutes, and Companies from Different Countries of the World Ultrasonic Nondestructive Testing-75, St. Petersburg, Russia, February 4–5, 2003.     

Inspection of fatigue defects in endurance testing of half-axles of maneuverable aircraft’s stabilizers by means of acoustic emission and tensometry

The results obtained by acoustic-emission (AE) testing and continuous tensometry in endurance testing of half-axles of maneuverable aircrafts stabilizers are described. In order to ensure the reliability of the tests, fractography of the fractures obtained is carried out along with metallographic studies of the materials structure in the zone of fracture nucleation and propagation.Translated from Defektoskopiya, Vol. 40, No. 9, 2004, pp. 3–10. Original Russian Text Copyright © 2004 by Sereznov, Maltsev, Stepanova, Kabanov, Chaplygin, Laznenko, Kareev, Kozhemyakin.     

Data-processing algorithms for automatic operation of ultrasonic systems with coherent data processing

Two algorithms for the automatic determination of flaw parameters during ultrasonic testing of welded joints with a high level of structural background noises are considered. The experimental data collected in the course of automated ultrasonic testing (AUT) using Avgur series with coherent processing of data (Avgur 4.2 and Avgur 5 systems) and the results of the assessment of nondestructive testing data are used. The first algorithm is used to identify zones where flaws may be located. This algorithm is applied after running AUT in the search mode. If the parameters of the algorithm application are selected properly, this algorithm makes it possible to determine the coordinates and the conventional length of the identified flaws. The second processing algorithm is intended to determine the flaws actual length and height. For its operations the algorithm uses the images obtained from coherent data processing. Results of testing methods for automatic (computer) determination of flaw parameters are cited. These results are obtained by the Avgur system during testing of austenite welded joints in stainless-steel pipes with a diameter of 325 mm and in perlite-steel pipes of various diameters.Translated from Defektoskopiya, Vol. 40, No. 12, 2004, pp. 3–15.Original Russian Text Copyright © 2004 by Badalyan, Vopilkin, Dolenko, Orlov, Persiantsev.This revised version was published online in April 2005 with a corrected cover date.     

The effect of cold plastic deformation and subsequent annealing on the magnetic properties of metals with different initial structures

The effect of the degree of cold plastic deformation (CPD) and the temperature of subsequent annealing on the coercive force, relaxation magnetization, and relaxation magnetic susceptibility of iron and nickel is studied. The effect of the degree of CPD on steels with different initial structures in the annealed state (such as ferrite (M 10 steel), pearlite (X15 steel), and ferrite-pearlite (50 steel) structure), as well as on 50steel with different initial structures obtained after quenching and tempering at different temperatures, is also studied. The dependences obtained are analyzed based on modern theories of magnetic hysteresis for magnetically soft materials. Recommendations for the use of nondestructive testing of the degree of CPD of articles (semifinished items) made from steels with different initial structures are given.Translated from Defektoskopiya, Vol. 40, no. 9, 2004, pp. 51–62. Original Russian Text Copyright © 2004 by Bida, Sazhina.     

Analysis of signals observed from the lateral surface during ultrasonic testing of a cylindrical article with a normal probe

The signals (up to the second bottom signal) observed from the lateral surface during ultrasonic testing of a cylindrical article with a normal probe are studied. The amplitude of the second bottom pulse is compared with that of the first bottom pulse. It is shown that one of the observed pulses is due to the rereflection of a longitudinal wave from a cylindrical surface in the cross-sectional plane that passes through the probes center, while the other pulse is due to the twofold reflection of an elastic wave with mutual transformation of longitudinal and transverse waves.Translated from Defektoskopiya, Vol. 40, No. 11, 2004, pp. 3–14.Original Russian Text Copyright © 2004 by Danilov.     

Methodological aspects of assessment of the strength and residual service life of pressurized vessels based on acoustic-emission diagnostics

The state-of-the-art in acoustic-emission diagnostics of pressurized vessels is analyzed. It is shown that the widely used qualitative relationship between nondestructive testing methods and the science of material strength can be replaced with a quantitative relationship based on specially organized non-destructive testing procedures carried out when the object being tested is operated. Based on a number of examples, in which the state of pressurized vessels subject to low-temperature hydrogen (hydrogen sulfide) corrosion and to pitting corrosion is assessed, the main concepts and options of the suggested methods are described. Results of the assessment of the residual service life of some vessels are presented. The conducted research shows that a new regulatory framework needs to be developed for assessing the operability of expensive equipment in oil-refining and petrochemical plants on the basis of acoustic-emission diagnostics, applied fracture mechanics, and risk analysis.Translated from Defektoskopiya, Vol. 40, No. 11, 2004, pp. 50–61.Original Russian Text Copyright © 2004 by Volkovas, Dorosevas, Elmanovich, Bagmutov.     

A new method for determining particle energy in the range 1011−1015 eV and results from a beam test at 180 GeV/c

A method for measuring the energy of the nuclear component of cosmic rays is described. The principle of the method consists in determining the energy of a primary nucleus from the space density of secondary particles produced in a thin target in the initial event of inelastic interaction. The results from testing the method on an ejected 180-GeV pion beam are presented. Analysis of the experimental data and simulation show that, using this method, it is possible to measure the particle energy with a relative error of 67%. The method is being developed for the direct detection of cosmic rays over wide ranges of energy (10¹¹–10¹⁵ eV/particle) and charge (Z = 1–30) during a cosmic experiment in near-Earth space.Translated from Pribory i Tekhnika Eksperimenta, No. 1, 2005, pp. 46–51.Original Russian Text Copyright ¢ 2004 by Bashindzhagyan, Voronin, Golubkov, Grebenyuk, Egorov, Kalinin, Karmanov, Konkov, Korotkova, Kozlov, Krumshtein, Merkin, Panasyuk, Pakhomov, Podorozhnyi, Postnikov, Roganova, Sadovskii, Sveshnikova, Sidorov, Tkachev, Turundaevskii.     

Experience of Using the Nondestructive Quality Testing for Articles from 40Kh Steel

Nondestructive methods for testing the hardness of articles made of 40Kh steel and subjected to quenching, including stepwise (warm) hardening with post-quenching, and subsequent tempering on various temperature intervals are considered.     

Eddy-current inspection of tubes in a nonuniform field

The problem of inspecting tubes and tubular articles from the inside in a nonuniform field of a through-type eddy-current transducer is considered. Based on an analysis of the transducers signal, sensitivities to the inspected tubes wall thickness and to changes in the electric conductivity are calculated. The inspection is optimized and the appropriate plots are presented.Translated from Defektoskopiya, Vol. 40, No. 8, 2004, pp. 38–49. Original Russian Text Copyright © 2004 by Dyakin, Sandovskii, Dudarev.     

Progress in the theory of ultrasonic flaw detection. Problems and prospects

This paper was prepared upon request from the organizers of the XVIII St. Petersburg conference Ultra-sonic Flaw Detection in Metal Structures. UZDM 2004. The progress made in the theoretical issues of ultrasonic flaw detection over the past 20 years is briefly considered, and some practical issues are discussed. Specific problems that are waiting to be solved are formulated, and the authors opinions about the prospects of developments in ultrasonic flaw detection are presented. The preparation of the paper was much facilitated by book [1], which was published recently.Translated from Defektoskopiya, Vol. 40, No. 10, 2004, pp. 13–48.Original Russian Text Copyright © 2004 by Ermolov.     

The effects of manganese content and mould size on abrasion and slurry erosion behaviour of chromium–manganese iron systems investigated by positron lifetime spectroscopy

Abrasion and slurry erosion behaviour of chromium–manganese iron samples with chromium (Cr) in the range 16–19% and manganese (Mn) at 5 and 10% levels have been characterized for hardness followed by microstructural examination using optical and scanning electron microscopy. Positron lifetime studies have been conducted to understand the defects/microporosity influence on the microstructure. The samples were heat treated and characterized to understand the structural transformations in the matrix. The data reveals that hardness decreased with increase in Mn content from 5 to 10% in the first instance and then increase in the section size in the other case, irrespective of the sample conditions. The abrasion and slurry erosion losses show increase with increase in the section size as well as with increase in Mn content. The positron results show that as hardness increases from as-cast to heat treated sample, the positron trapping rate and hence defect concentration showed opposite trend as expected. So a good correlation between defects concentration and the hardness has been observed. These findings also corroborate well with the microstructural features obtained from optical and scanning electron microscopy.     

Magnetic-field strength meter MΦ-207

The operating principle is described and the technical specifications are reported for the M-207 instrument that measures small (up to 3000 A/m) and large (up to 300000 A/m) magnetizing-field strengths using a flux-gate meter and a Hall transducer, respectively.Translated from Defektoskopiya, Vol. 40, No. 8, 2004, pp. 34–37. Original Russian Text Copyright © 2004 by Vatolin, Menshchikov, Shanaurin, Shcherbinin.     

Studies of the fracture process in composite structural elements based on strain measurements and the acoustic-emission technique

The results of cyclic tests of structural elements (SEs) with a stringer, which are made of the composite material (CM) Organit-10T and are parts of an aileron from an ë-80Éè aircraft, are considered. As SEs are broken, information is obtained simultaneously from acoustic-emission (AE) and tensometric equipment and measurements of the fatigue cracks opening are carried out. An insignificant increase (by 0.25 µm) of the crack opening generates a considerable flow of AE signals. These signals are processed using cluster analysis, which makes it possible to separate the signals emitted by a propagating fatigue crack in the stringer region from the signals arriving from the region of the fracturing gripping jaw.Translated from Defektoskopiya, Vol. 40, No. 9, 2004, pp. 11–18. Original Russian Text Copyright © 2004 by Sereznov, Stepanova, Lebedev, Chaplygin, Katarushkin, Kozhemyakin.     

The possibility of testing the structural state of highly-deformed high-carbon steels by the magnetic method

The influence of cold plastic deformation on phase transformations and on the magnetic properties of powder specimens of the Fe-5-at. % C alloy modeling U12 high-carbon steel has been investigated in the context of nondestructive testing. It has been shown that under high plastic deformation dissolution of cementite Fe3C occurs by the scheme -Fe + Fe₃C -Fe + (Fe₃C)_d + -Fe + Am(Fe-C). An increase in the rate of plastic deformation of powders decreases the coercive force from 50 to 13 A/cm due to the low coercivity of the #x03B1;-Fe and Am(Fe-C) phases. The structural state of high-carbon steels following a strong cold plastic deformation can be determined by measuring two magnetic parameters: the coercive force, and the temperature dependence of differential magnetic permeability.Translated from Defektoskopiya, Vol. 40, No. 7, 2004, pp. 42–52.Original Russian Text Copyright © 2004 by A.I. Ulyanov, Arsenteva, Zagainov, A.L. Ulyanov, Elsukov, Dorofeev.     

Specifics in the magnetic-thickness measurement of galvanic nickel deposits

The level of internal stresses appears to be the main interfering factor in the magnetic measurement of the thickness of nickel deposits. The possibility of development of a probe with an informative zone close to magnetic saturation, which would substantially decrease the effect of stresses on measurement results, is demonstrated.Translated from Defektoskopiya, Vol. 40, No. 11, 2004, pp. 62–68.Original Russian Text Copyright © 2004 by Shukevich, Lukhvich, Kremenkova, Lukyanov, Sharando.     

On reconstruction of cracks with interacting edges

A method for the reconstruction of the configuration of cracks is suggested based on finding heat sources that model the interaction between cracks edges (such as friction and collapse) in solids exposed to external ultrasound. The input information for reconstruction is a stationary temperature field on a solid boundary. The functional of nonreciprocity was constructed; the study of this functional made it possible to convert the problem of determining a cracks parameters into a few transcendental equations; explicit formulas were obtained for small cracks. The results of computational experiments on reconstruction of the parameters of a straight crack are considered.Translated from Defektoskopiya, Vol. 40, No. 10, 2004, pp. 62–69.Original Russian Text Copyright © 2004 by Vatulyan, Solovev.     

The capacities of modern EMA thickness gages

The literature concerned with the problem of studies and development of thickness gages based on the EMA method of exciting and detecting ultrasound pulses is analyzed. A new approach to the design of EMA thickness gages is developed. A prototype of the manual EMA thickness gage is designed and tested. It is shown that the EMA device offers considerable benefits when using the correlational data processing.Translated from Defektoskopiya, Vol. 40, No. 12, 2004, pp. 16–25.Original Russian Text Copyright © 2004 by Suchkov.This revised version was published online in April 2005 with a corrected cover date.     

Wear resistant solid lubricant coating made from PTFE and epoxy

A composite coating of polytetrafluoroethylene and epoxy shows 100 × improvements in wear resistance as compared to either of its constituents alone and reduced friction coefficient under testing on a pin-on-disk tribometer. This coating is made by impregnating an expanded PTFE film with epoxy, which provides three unique functions: (1) the epoxy compartmentalizes the PTFE nodes, which is believed to reduce the wear of the PTFE, (2) the epoxy increases the mechanical properties such as elastic modulus and hardness, and (3) the epoxy provides a ready interface to bond the films onto a wide variety of substrates easily and securely. The experimental matrix had normal loads of 1–3 N, sliding speeds from 0.25 to 2.5 m/s, and used a 2.4 mm radius low carbon steel pin in a rotating pin-on-disk tribometer. The skived PTFE films had wear rates on the order of K=10^–3 mm³/Nm and friction coefficients around =0.2. Both the high density films (70 wt%PTFE) and low density films (50 wt% PTFE) had wear rates on the order of K=10^–6 mm³/Nm and friction coefficients around =0.15. The neat epoxy films showed significant scatter in the tribological measurements with wear-rates on the order of K=10^–4 mm³/Nm and friction coefficients around =0.40. The enhanced tribological behavior of these composites is believed to stem from the coatings ability to draw thin PTFE transfer films into the contact from the nodes of PTFE, which act like reservoirs. Nanoindentation mapping of the coatings and the transfer films supports this hypothesis, and accompanies scanning electron microscopy observations of the worn and unworn coatings.