Phased Array Ultrasonic Testing:

Basic concepts:
The distinguishing feature of the phased array ultrasonic testing is the computer controlled excitation of the individual elements in a multielements probe. The excitation of these multiple piezo composite elements generates a focused ultrasonic beam, allowing the dynamic modification of the beam parameters such as angle, focal distance and focal spot size through software. To generate beam in phase by means of constructive interference, the various active elements are pulsed at slightly different times. Similarly, the echo from the desired focal point hits the various elements with a computable time shift.
The echoes received by elements are time shifted before being summed together. The resulting sum in an A-scan that emphasizes the response from the focal point and attenuates from other points in the test piece.

Advantages:
Multiple angle scan possible Interpretation Simple More Production rate data storage reproducibility Setup time between inspections decreased 100% volume inspection in single Scan Better sizing of Defects.

Applications:
Inspection of girth welds of Pressure vessels Corrosion Mapping laminations checking Tube and pipe weld inspections Inspection of Tee-joints issimmilar weld inspection Power plant Nozzle Testing.