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Том 54, № 9 (2018)
- Год: 2018
- Статей: 6
- URL: https://journals.rcsi.science/1061-8309/issue/view/11344
Acoustic Methods
Estimating the Probability of Detecting a Delamination in the Wall of Equipment Depending on the Set of Used Methods of Nondestructive Testing and Ways of Its Improvement
Аннотация
A method is proposed for assessing the quality of nondestructive testing and the technical condition of tanks and vessels used in petrochemical industries, depending on the methods of nondestructive testing employed in technical diagnostics. The probability of revealing a defect was used as a criterion when assessing the quality of technical diagnostics. Estimates are given for the probability of detecting a delamination in the vessel-body wall material of different area using various schemes of applying the basic methods of nondestructive testing. It is shown that the acoustic-emission method makes it possible to significantly increase the probability of detecting a delamination in the equipment wall without increasing the scope of work by virtue of local methods of nondestructive testing. A positive effect is achieved through the use of acoustic-emission testing data (the location maps and hazard levels of acoustic-emission sources) at the stage of planning the procedure of nondestructive testing during technical diagnostics of equipment.
619-629
Ultrasonic Flaw Detection: Adjustment and Calibration of Equipment Using Samples with Cylindrical Drilling
Аннотация
Questions related to adjusting an ultrasonic flaw detector using cylindrical bores in reference and tuning samples are considered with allowance for the specific features of single- and double-crystal testing schemes, including when a bore is sonified perpendicularly and at an angle to its axis. Requirements have been determined in each scheme to the drilling diameter and the duration of ultrasonic pulses such that signals specularly reflected from the drilling surface not be distorted by creeping and other signals diffracted by the cylinder. It is indicated that under these conditions, cylindrical drilling can be used not only for adjusting the “flaw detector–transducer” system, but also for calibrating the time scan, verifying the accuracy of the depth gage, and checking the flaw-detector attenuator. This approach makes it possible to simplify the construction of measures and tuning samples by eliminating excess reflectors. Examples are given in the echo and TOFD techniques for testing welded joints using traditional and special double-crystal schemes with different probes orientations.
630-637
Investigation of Acoustic Emission in Low-Carbon Steels during Development of Fatigue Cracks
Аннотация
AE control results for cyclic tests of metal samples with a notch are presented. The main stages of the fatigue crack development and standard AE parameters are matched. A criterial plane which allows to separate clusters corresponding to the stages of stable and avalanche-like defect growth has been constructed. It is shown that the boundaries of clusters remain unchanged irrespectively to the differences in the kinetics of damage development.
638-647
Electromagnetic Methods
Effect of Plastic Deformation on the Magnetic Properties of Rapid-Quenched Cobalt-Based Metal Wires
Аннотация
The effect of plastic deformation on the magnetic parameters of rapid-quenched nanostructured Co66Fe4Nb2.5Si12.5B15 wires was established for the first time, as well as their sensitivity to tensile stresses. Plastic deformation changes magnetic anisotropy induced by the rapid quenching of cobalt-based metal wires, and, as a consequence, determines their magnetic parameters. Remanence is a characteristic that is most sensitive to plastic deformation. A conclusion is drawn that plastic deformation of wires leads to an increase in magnetostriction constant.
648-653
DIUS-1.15M Mobile Hardware–Software Structuroscopy System
Аннотация
It is shown that by measuring the magnetic field in a specially shaped hole made in the magnetic circuit of a measuring transducer and the tangential component of the magnetic field in the transducer’s interpolar space near the surface of an object being magnetized, it is possible to locally determine the relative values of the magnetic properties of the test-object substance. The physical rationale is provided for a technique that makes it possible to determine the entirety of hysteresis characteristics and significantly expand the ranges of measurement of magnetic properties. The difference is established between the structural sensitivities of magnetic properties locally determined in terms of “flux–internal field” (the properties of matter) and “flux in the product–current in the windings” (the properties of “body”) coordinates. It is shown that it is possible and expedient to simultaneously measure and jointly analyze the magnetic characteristics of matter and “body”. Information is provided on the DIUS-1.15M mobile hardware–software system, intended for implementing single- and multiparameter techniques of monitoring the structure–phase and stress–strain states of ferromagnetic materials and objects based on the proposed measurement procedures.
654-661
X-Ray Methods
Comparative Analysis of Various Definitions of the Concept of Effective Atomic Number of Material of a Multicomponent Object
Аннотация
Comparative analysis is provided for various definitions of the concept of effective atomic number as applied to the material of a multicomponent object. Definitions in which radiation is and is not taken into account explicitly have been considered. Results of calculating the effective atomic numbers of various substances are presented on the basis of the definitions considered. New formal definitions are proposed for this concept when X-raying a multicomponent object with polychromatic radiation.
662-674