PAUT is an advanced method of ultrasonic testing. Instead of a single element and beam, phased array uses multiple ultrasonic elements and electronic time delays to create beams by constructive and destructive interference. PAUT offers significant technical advantages for weld testing over conventional ultrasonic as the phased array beams can be steered, scanned, swept and focused electronically from a fixed probe position. Beam steering permits the selected beam angles to be optimized ultrasonically by orienting or focusing them perpendicular to the predicted discontinuities.
- Shell to Dish End Joints
- Circular Seam & Long Seam Welds, Joints, T-Joints
- Category D Joints / Pressure Part, Weld-o-lets, etc.
- Structural Welds, Knuckle joint, etc.
- SS & AS Cladded plate Joints
- Boiler Weld Joints (Dia. 1.5” – 4”)
- High-speed inspection using single-axis scans instead of conventional raster scan
- Near-optimal focal length and focal spot for various areas of complex parts or thick components
- Small, simple probe assembly with multiple beams from a single probe
- Easy-to-install, one-axis scanning systems
- Better detection in austenitic materials and dissimilar metal (DM) welds
- Alternative to Radiographic imaging
- Full record of examined weld sections in A-Scan, B-Scan, C-Scan, D-Scan and TOFD Scan presentation. Storage of full examination results
- Real Time vision on quality of welds by the operator during examination
- Accuracy in sizing the through thickness dimensions
- High sensitivity in detecting planar, vertical or oriented defects like cracks or lack of fusion not visible by radiography and hardly to detect by standard ultrasonic pulse echo technique. For these reasons ASME Code with the Code Case 2235 has permitted to perform on pressure vessel welds TOFD examination in lieu of radiography
- Full control on contact effectiveness and coverage by examining the TOFD map in any time after the examination
- Supervision of the examination in the dynamic way as during the scanning on your PC in the office or far away the job
Source :- https://www.ndts.co.in/weld-inspection-by-advance-ultrasonic-paut-tofd/