The advantages and disadvantages of radiography and automated ultrasound control (AUZK) with coherent data processing are considered. The informativeness and sensitivity of these methods are compared. The possibilities of measuring the size of defects in radiography and in AUZK are analyzed. It is argued that for practical purposes, the detectability and error in determining the geometric dimensions of defects in AUZK with coherent data processing is quite sufficient. An example of using a system with coherent data processing for monitoring austenitic welded joints of pipelines of considerable thickness — up to 45 mm is given. The pipelines were used in the construction of a catalytic cracking complex. The timing of the work showed that the performance of the AUZC of one welded joint Ø 508 × 34 mm did not exceed 60 minutes, with the possibility of carrying out other installation work.
The article describes an approach to measuring the equivalent area of discontinuities in ultrasonic testing using phased arrays by calculating generalized ARD diagrams. The description of the calculation model, experimental results of checking the accuracy of calculations, information about the application of the proposed technology in the software of AUGUR series systems are given. The idea of generalized ARD diagrams (FAR-ARD) is to construct a three-dimensional function that establishes the relationship between the amplitudes of echo signals reflected from a flat-bottomed hole with a diameter d removed at a distance r from the beam entry point with an input angle of degrees for a given focusing law.
The method of automated control based on the use of a headlight-flaw detector for recording echo signals with subsequent restoration of the image of reflectors by projection in spectral space in three-dimensional mode (3D-PSP) is considered.A special setting of the flaw detector allows you to simulate the operation of many single-element converters with different input angles. This approach makes it possible to obtain images of reflectors with high resolution and a high signal-to-noise ratio at a depth of more than 100 mm. The procedure of calibration of an antenna array on a prism operating in the simulation mode of several piezoelectric converters with different input parameters is considered. The results of the control of the fragment of the ITER divertor support workpiece when obtaining images by the classical method of headlights and using three-dimensional processing are presented, demonstrating the effectiveness of the developed control technology.
A method for determining an unknown velocity of propagation of shear ultrasonic waves and an unknown thickness of the object of control is considered. It is proposed to use two antenna arrays operating in double scanning mode, when echo signals emitted and received by all pairs of antenna array elements are recorded. Antenna arrays on prisms are installed on the surface of the object of control in the direction "to each other". An algorithm for processing the measured echo signals using a method similar to the least squares method has been developed. The use of the algorithm makes it possible to determine simultaneously the speed of sound and the thickness of the control object with plane-parallel boundaries with an accuracy of at least 0.5%. The article examines the factors affecting the accuracy of measurements, suggests ways to eliminate or minimize them. The results of numerical experiments and the results of applying the method on three samples with comparison with the measurement results of the IN-5101A device are presented.
The features of image formation of reflectors using phased array antenna technology and images obtained by the C-SAFT method from echo signals measured in the double scanning mode are considered. It is shown that in some cases the images obtained using phased array technology are less informative. While the images obtained by the C-SAFT method have a higher frontal resolution in the entire image recovery area, partial images recovered at different positions of the antenna array can be coherently folded, which allows to obtain a high and uniform resolution in the entire volume of thick-walled products and increase the signal-to-noise ratio. The registration of echo signals in the dual scan mode and the restoration of the image of reflectors by the C-SAFT method will be called digital focusing by the antenna array (CFA) for short. The ability to restore partial images of reflectors using once-measured echo signals from many acoustic circuits, followed by their combination into one high-quality image, should allow reliably automating the process of recognition and measurement of diffusers. Another advantage of the images obtained by the C-SAFT method with three-dimensional focusing is the ability to restore images in a single coordinate system when using antenna arrays on prisms of different configurations. This facilitates collaborative image analysis. The rates of image formation using phased array technology and images obtained by the C-SAFT method are comparable. If the control technique is based on the use of nonlinear effects, then in this case, the headlight flaw detectors have an undeniable advantage over the CFA flaw detectors. But within the framework of linear acoustics, the headlight flaw detectors have no fundamental advantages over the CFA flaw detectors. It is fairer to say that the headlight flaw detectors have disadvantages. The article presents images illustrating the features of images obtained by FAR and CFA flaw detectors.