Estudio y selección de la técnica de ultrasonido industrial para una confiable detección de discontinuidades en juntas soldadas

Abstract

The technological advances that have occurred in Non-Destructive Testing (NDT) have allowed companies to place greater emphasis on their development, with ultrasound being the most widely used volumetric non-destructive technique in the industry. The objective of this study is to determine the most reliable ultrasonic technique in the detection of discontinuities in welded joints, for which inspections were carried out with the techniques: Conventional Pulse-Echo Ultrasound, Phase Array Ultrasound and TOFD. Welding specimens with induced discontinuities were made, starting from processes qualified by the API 1104 standard, these processes were carried out by welders qualified with API stamp, who based on their experience managed to obtain the most common discontinuities mentioned in the API 1104 code. simulating a daily environment, the inspector had no knowledge of the type of discontinuities that were induced in the test tubes. To inspect the welded joints, the SONATEST model VEO 16:64 equipment was used, which provides the facilities to carry out inspections with the different techniques used in this study, its calibration was carried out under the inspection of an ASNT level II technician. The welding specimens were inspected, keeping a record of the data, which were analyzed and statistically compared, obtaining as a result that the ultrasound technique with the highest reliability is the Semiautomatic Phase Arrangement Ultrasound with a 84% probability of detection of discontinuities. It is recommended to have an exact control of the position of the transducer to the center of the weld, to avoid that at the time of the inspection the transducer moves too far or close to the weld bead and misinterpret the echoes.