Detecting surface and volume defects in metals by the laser-acoustic method

Increasing the laser-acoustic method efficiency for testing metal products by using 3D visualization

“…The present work is a logical continuation of the researches conducted by the authors earlier [11][12][13][14] and aims to improve proposed laser-acoustic method in terms of the increase of defect detection sensitivity and probability of detection microcracks in metals. Also, it is important to get information about the shape of defect for determine the level of its criticality.…”

“…Proposed methods allow not only the detection of various types of defects in metals, but also their location and parameters (depth, width, length). In [13], for the first time, an attempt was made to develop a unified concept of laser-acoustic testing based on uniform equipment and analysis of surface acoustic wave (SAW) propagation parameters through a defect area when studying various control objects and defect types. Such an approach makes it possible to consider a combination of several methods as applied to different control objects as a single laser-acoustic method for detecting surface, near-surface and defects in metals and discontinuities in metal films.…”

“…The first one is based on scanning the surface of an CO by a laser beam when a piezoelectric transducer (PET) fixedly mounted on the CO surface, the second one is based on the synchronous movement of the PET along with a laser beam with a fixed distance between them. The results of studies published in [11][12][13][14] were obtained using only the first mode. The fixedly mounted PET has a more stable acoustic contact with the CO surface and can significantly reduce the instrumental error in analysing the amplitude of the detected surface wave in case of detection of discontinuities in metal films and near-surface defects in metal products.…”