Обследование скрытых участков стальных труб малого диаметра с применением ультразвуковой дефектоскопии

Abstract

According to the current regulatory documents, as the established service life of gas pipelines for various purposes expires, they must be inspected in order to assess the current technical condition, make a decision on the residual life and the possibility of further operation at hazardous production facilities, as well as other buildings and structures. The possibility is considered related to using ultrasonic testing for detecting damage of corrosion origin in the sections of such pipelines hidden from the direct observation in interfloor ceilings and passages through the walls of buildings at the facilities in various branches of industries, as well as in gas distribution and gas consumption systems, and water pipelines. In addition, the possibility of identifying layered deposits of various origins in the cavity of small-diameter steel pipes is considered. At energy facilities, as well as in water supply pipelines, such deposits can lead to a significant reduction in the flow area of the pipeline, up to its complete blocking. Deposits inside the pipelines form an anisotropic layered medium, and the passage of ultrasonic waves through it has a number of features that prevent the use of traditional ultrasonic echo testing. For small-diameter pipes, the criterion is given under which it is possible to perform «remote» (waveguide) ultrasonic testing of the hidden sections of pipes at a distance of up to 600 mm. It is illustrated how, from such a distance, it is possible to detect corrosion deposits in pipes by ultrasonic testing methods using phased array antennas. At the same time, it is possible to assess the thickness («power») of layered deposits and their structure even when the passage section of the pipeline is filled with such deposits up to 100 %. Use of the methods presented in the article allows to increase the accuracy of calculating the residual life of the pipeline and reduce the uncertainty in setting safety factors in such calculations.