Susceptibility of Penetrant-Dye Testing as a Function of Development Temperature

The paper considers the effect of heating temperature of tested components on the stage of development in penetrant-dye tests on their susceptibility. Analytical expressions are given for calculating the optimal penetration depth due to diffusion in cylindrical flaws and threshold parameters of detected flaws with due account of the heating. By heating a tested object both before the penetrantdye deposition on the surface and on the stage of development, one can obtain optimal results in terms of the sensitivity and duration of the stage on which the penetrant is used.     

Use of the Harmonic Analysis of an Induction Probe's Signal for Increasing the Information Content of Test Results

The harmonic content of a probe's electromotive force when magnetic testing is conducted with the use of alternating fields is significantly affected by the possible presence of a flaw in the specimen. Magnetic biasing of the specimen with a static field enables identification of internal flaws in addition to surface flaws. The electromotive force's harmonic content depends on the flaw's dimensions and depth. This circumstance can be used to determine these parameters in a separate way. The effect of a gap between the surface of a tested specimen and the probe is significantly weaker on the topography and amplitude of higher harmonics than on the corresponding parameters of the first harmonic. This observation, which holds for both internal and surface flaws, enables testing of larger gaps.     

Evaluation of the Size and Type of Flaws in a Railhead

The relevance of being able to detect flaws beneath horizontal exfoliations in rails with simultaneous measurement of crack parameters has been shown. Based on the performed research, the authors proposed a new method for revealing transverse cracks (including beneath surface damages) in railheads and evaluating their parameters. The method is based on a multichannel implementation of ultrasonic through-transmission inspection and on processing of the results of layerwise scanning of a tested rail section. Pilot field tests with a new defectoscope that implements the proposed method have shown that the device is capable of revealing the above flaws in railheads, with the measurement error not exceeding 15%.     

Acoustic-emission quality control of plastically deformed blanks

The questions of modeling the process of failure under plastic restructuring of a material, the transformation of the strength state of the material of plastically deformed blanks into the state of the article material, the acoustic-emission assessment of the faultiness of the end item, and the liability of the flaws in a blank to development under rolling are considered.     

Computer analysis of the configurations of magnetic fields of subsurface discontinuities of finite dimensions and arbitrary shapes in tested objects of finite length by the method of spatial integral equations

Using software developed by the authors and based on the method of spatial integral equations, the spatial configurations of the magnetic fields of tested objects of finite length that contain subsurface discontinuity flaws of finite dimensions and arbitrary shapes are studied. It is possible to take into account the influence of both uniform and nonuniform magnetizing fields, including real sources; an arbitrary geometry of tested objects; and a nonlinear character of the magnetic properties of materials. It is shown that software can be used in studies of the influence of the geometrical parameters of a defect on the topography of the informative magnetic field in the testing zone.     

Application of the inverse diffraction technique to the problem of reconstruction of complexly shaped flaws by ultrasonic methods

The methods used in inverse diffraction problems and applied to the problem of reconstructing flaws of complex shapes using ultrasonic scanning are reviewed. The application of the theoretical methods developed by the authors is described in more detail. The accuracy in reconstruction of flaws on the basis of a new proposed method is tested.     

Identification of sources of acoustic emission on casting flaws in cast parts

Peculiarities of the estimation of the state of sections with casting flaws in cast parts using acoustic-emission (AE) method are considered. The dynamics of variations in AE parameters for developing flaws during mechanical tests is analyzed. The methods for distinguishing useful information of AE signals from the regions of localization of casting flaws are revealed.     

Problems of engineering diagnostics of electron-beam welding

Features of electron-beam welding (EBW), various types of flaws arising in welded joints during EBW, and the factors causing these flaws’ appearance are considered. The effects of beam focusing and the thickness of the welded metals on the shape of a seam are demonstrated. EBW flaws are classified. The difficulties associated with obtaining informative parameters during EBW are analyzed. Radiation and acoustic methods for engineering diagnostics of EBW are considered. New approaches to the construction of systems for diagnostics of EBW are proposed. Experimental results are presented.     

Analysis of errors in location of flaws in multipass welds using different clustering methods

Titanium and duralumin inserts were introduced into a weld to imitate welding flaws in St3 steel samples. Analysis of the accuracy of locating the introduced flaws with different clustering methods (by digitized shape, main informative parameters, the rise rate of leading-edge envelope) has shown that these methods involve considerable time expenditures. The developed dynamic clustering has been combined with the clustering by main informative parameters and allowed in situ location of flaws during welding, while the weld has not been completed yet.     

槽形缺陷对超声波反射当量的研究

这里旨在探讨超声波作用于不同种类槽形缺陷上的反射规律，找出适用于单面对接焊缝超声波探伤的参考槽形，指出测定单面焊缝根部缺陷，特别是测定裂纹缺陷可能出现的误差。通过实验测定。检验了槽形缺陷的定量计算公式，指出了符合定量计算公式的条件和适用范围。     

Dependence of the magnetic field of a flaw on the distance to the surface of a tested article

The dependence of the magnetic field of a flaw on the distance to the surface of a tested article has been studied for rectangular slot-type flaws. For flaws with a small opening width, it can be considered that their magnetic field decreases in inverse proportion to this distance, but with an increase in the flaw width, the field decreases more slowly.     

Measuring Geometric Parameters of Discontinuity Flaws in Ferromagnetic Plates by Minimizing Smoothing Functional. II. Estimates of Discontinuity Flaw Parameters

Estimates of geometric parameters of fabricated flaws in artificial samples are given.     

A two-step algorithm for finite-element solution of electromagnetic-testing problems: Eddy-current testing

An algorithm for finite-element simulation of eddy-current testing problems is described. This algorithm allows calculation of transducer signals from any 3D flaw in a metallic item. In practice, the studied flaws are often characterized by small dimensions. Therefore, the measured increment of the voltage induced in the transducer’s output winding owing to the presence of such a flaw is only several percent of the voltage’s average value. If a standard calculation scheme based on the finite-element method is applied, significant computational resources are needed to solve this problem. The two-step algorithm allows a significant reduction in the required resources. The essence of the algorithm is that the source of the field of a flaw’s effect is determined from the distribution of eddy currents in metal free of flaws. Such an approach allows the calculations of the “unperturbed field” to be simplified significantly through consideration of the geometric symmetry of the problem solved and thus, through reduction of its dimensionality. The efficiency of the two-step algorithm is demonstrated during the solution of a typical problem: the use of a through differential transducer for eddy-current testing of a segment of a heat-exchange pipe in the steam generator of a nuclear power plant.     

Evaluating Efficiency of Nondestructive Detection of Flaws in Concrete

Tests have been performed to assess feasibility of using the impact-echo method (IEM) and ultrasonic pulse velocity method (UPVM) in detecting flaws and evaluating their depths on the early stage of a concrete structure's service life. Five reinforced concrete (RC) slabs of grades 25, 30, 40, and 50 with fabricated voids at known locations were studied on the 3rd, 7th, 14th, and 28th day. The results were compared to estimate the accuracy of both methods and their efficiency. Both methods detected flaws in the tested samples on the early stages of their operation. Depth measurements of flaws by IEM, however, are more accurate. Results of our tests indicate that both methods can be used in determining depths of flaws in concrete and in performing on-site tests. The accuracy of both methods proved to be better in tests of stronger concretes, and the detection probability ranged from 51.81 to 99.8% after aging during 3 to 28 days under full load, respectively.     

Specific Features of Excitation and Propagation of Longitudinal and Transverse Subsurface Waves in Solids: I. Waves in Objects with a Free Plane Boundary

Specific features of excitation and propagation of transverse and longitudinal subsurface waves in solids are determined. Dependences of the parameters of the acoustic field generated in a solid body on the acoustic properties of a probe's wedge and of the tested body are found experimentally and compared to theoretical results. Using the amplitude and the directivity characteristic of the principal transverse mode and of accompanying secondary modes (longitudinal and Rayleigh), the optimum solutions for identifying subsurface flaws characterized by low reflectivity are determined. Studies of the passage of an acoustic signal through a magnetic-fluid acoustic guide and analysis of the magnetic-fluid's acoustic properties enable conclusions to be drawn regarding expediency of the usage of such media for excitation (detection) of longitudinal and transverse subsurface waves in materials with low velocity of sound (plastic, etc.)     

A method for improving the accuracy of evaluating the dimensions of flaws in walls of tubular elements of structures

An algorithm for evaluating the real accuracy of the basic measuring instrument (exterior or in-tube flaw detector) in measuring parameters of flaws of a particular inspected tube was proposed on condition that the basic measuring equipment has no systematic error, while a verification instrument is considered as “absolutely” precise or “reference.” A statistical method of increasing the accuracy of evaluating the dimensions of flaws in thin-walled tube elements was developed on the basis of a correlation between the dimensions of flaw parameters. It can be taken as a basis for finding real values of parameters of flaws and for performing reliable calculations of the residual strength and residual life, for scheduling optimal periods for the next inspection of pipelines, and for ranging segments of a pipeline by a risk criterion, thus providing optimal scheduling of repairs.     

Methodological principles and techniques of ultrasonic acceptance tests of wheelset axles

The ultrasonic system designed for performing acceptance tests of wheelset axles of railway rolling stock during production with the aim of detecting metallurgical flaws and/or flaws caused by drawbacks in the manufacturing process is substantiated. The effect of the factors not regulated by the normative documents on the testing reliability, including the type and structure of probes, their location, and the surface state of a tested object, is analyzed. Recommendations for improving reliability and reproducibility of the acceptance test data on wheelset axles are formulated and confirmed experimentally.     

Current state of safety testing of main pipelines

The paper briefly describes the history of quality testing of buried main pipelines. The pioneering research into the development of magnetic techniques for detection of flaws caused by corrosion in pipelines has been conducted at the Institute of Metal Physics of the Ural Division of Russian Academy of Sciences. The fairly high accuracy of measured parameters of detected flaws is confirmed. The topical problems concerning pipeline testing are formulated. Deceased.     

Portable Magnetic Flaw Detector Equipped with a Magnetic Indicator Bag

The design of a magnetic flaw detector with a magnetic bag used as a flaw indicator is discussed. Technical parameters of the detector and those of detected flaws are given.     

Applying the Algorithm of Calculation in the Frequency Domain to Ultrasonic Tomography

Applying ultrasonic-tomography systems makes it possible to precisely determine the shape and dimensions of flaws with the aim of establishing the degree to which the flaws influence safe operation of tested objects. This problem is solved by using special algorithms that make use of echo-signals recorded by an ultrasonic transducer to generate synthesized images of flaws in the sample. The use of phased arrays in ultrasonic tomography is explained by their ability to provide exhaustive data about the internal structure of a test object, thus allowing formation of the high-quality synthesized images of flaws in the object. Increasing the speed of ultrasonic tomography by using phased arrays necessitates the development and implementation of fast data-processing algorithms. In this connection, of interest are calculation algorithms in the frequency domain, which ensure the high speed of producing synthesized images. An ultrasonic-tomography algorithm is proposed that is based on calculations in the frequency domain. The algorithm takes the complex nature of the propagation of ultrasonic waves into account and is connected with the presence of media with different acoustic properties (e.g., in the case of immersion tests). Possibilities offered by the algorithm are investigated by computer simulations using the licensed CIVA 2016 software package and experimentally.