Phased arrays are used for a wide variety of inspection and measurement applications, and they can be used for any job done by conventional ultrasonics. For example, phased arrays are used to detect and image defects including cracks , voids, and pits caused by corrosion (see video below). They are used to measure material and coating thickness, and to detect changes in material properties. Another common application is to assess the quality of welds and rivets. Phased arrays are also used to inspect joints and interfaces, for example, to detect and map adhesive.
Electronic scanning is a process that reproduces the inspection done by moving manually a standard UT probe. An ultrasonic beam that depends on the aperture selected is electronically translated across the entire probe. This allows for faster inspections and it limits the mechanical displacement. This technique can be combined with beam focusing and beam steering. This can be done using L-wave or S-wave.
A sector scan is a process used to control an ultrasonic beam by electronically changing the beam angles within a defined sector. This is done by applying electronic delay laws to the various elements of the array. This technique is an alternative to using several standard UT transducers with different wedges. The advantages are that only one transducer is needed to inspect components under several angles; it is much faster than angled beam standard UT and it displays in real-time a cross section of the specimen allowing for easier interpretation. This can be combined with electronic focusing and used for L- and S-waves.
TOTAL FOCUSING METHOD (TFM)
CORROSION MAPPING APPLICATION
This video shows a corrosion mapping inspection using a manual scanner and the real-time Total Focusing Method (TFM). The video shows different defects (corrosion close to the surface, pitting,...) in TFM and in Elecronic scanning, using the same probe position.