Phased Array Ultrasonic Testing system use multi-element probes, that are independently excited under computer control. Each element is excited in a controlled manner; a focused beam of ultrasound is generated. Software enables the beam to get steered.
Two and three dimensional views are generated which shows the locations and sizes of any flaws detected. The ability of testing welds with multiple angles with a single probe enhances the probability of detecting anomalies. Electronic focusing allows ooptimization of the beam shape and size at the expected defect location and optimizing the detection probability.
The capability to focus at multiple depths improves the ability for sizing critical defects for the volumetric inspections. By focusing, signal-to-noise ratio gets improved in challenging applications, and electronic scanning across many groups of elements that allows for C-Scan images to be produced very rapidly.
HydroFORM™, probe is designed to provide efficient inspection options for detecting wall thickness losses which occur due to corrosion, abrasion and erosion can be coupled with phased array systems for corrosion mapping.
Time of Flight Diffraction (TOFD) is based on the Principle of Diffraction in contrast to Reflection of ultrasound as used in conventional UT. Diffraction takes place at its extremities when ultrasound is incident at linear discontinuity such as crack. The depth of crack tips can be calculated automatically by trigonometry application by using the measured time of flight of the pulse. TOFD is very sensitive in detecting all the types of defect, irrespective of its orientation.
Advantages of TOFD
TOFD defect detection independent of the defect orientation, in contrast to the pulse echo technique Defect position and size can be exactly determined
No evacuation of areas during operation because no radiation is used